Anatomy: Head & Neck

Sternocleidomastoid Muscle .................. 2 Auditory Tube ...................................... 78

Scalenus Anterior Muscles .................... 4 Middle Ear Cavity ................................ 80
Anterior Triangle of the Neck ................ 5 Pterygopalatine Fossa ........................... 82
Posterior Triangle of the Neck ............... 7 Cutaneous Innervation of Face ............. 83
Thyroid Gland ........................................ 9 Glossopharyngeal Nerve (9th Cranial
Common Carotid Artery ...................... 11 Nerve) ................................................... 85
External Carotid Artery........................ 13 Vagus Nerve (10th Cranial Nerve) ........ 86
Internal Carotid Artery (Cervical Part) 15 Accessory Nerve (11th Cranial Nerve) . 88
Subclavian Artery ................................ 17 Hypoglossal Nerve (12th Cranial Nerve)
Internal Jugular Veins .......................... 19 .............................................................. 89
Cervical Plexus .................................... 21 Paranasal Sinuses ................................. 91
Phrenic Nerve (Cervical Part) .............. 22 Oral Cavity ........................................... 93
Cervical Part of Sympathetic trunk ...... 23 Palate .................................................... 94
Trachea (Cervical Part) ........................ 25 Pharynx ................................................. 96
Lymphatic Drainage of the Head & Neck Oropharynx ........................................... 98
.............................................................. 27 Laryngopharynx ................................. 100
Scalp..................................................... 29 External Ear ........................................ 101
Facial Artery ........................................ 31 Larynx ................................................ 102
Facial Nerve ......................................... 32
Dura Mater of the Brain ....................... 34
Cranial Fossae ...................................... 36
Cavernous Sinus................................... 37
Superior Sagittal Sinus ......................... 39
Middle Meningeal Artery .................... 40
Types of Intracranial Hemorrhage ....... 41
Cerebral Hemorrhage ........................... 42
Internal Carotid Artery (Petrous,
Cavernous & Cervical Parts) ............... 43
Trigeminal Ganglion ............................ 44
Structure of the Eyeball ....................... 46
Movements of the Eyeball ................... 48
Ophthalmic Artery ............................... 50
Lacrimal Apparatus .............................. 51
Vertebral Artery ................................... 52
Parotid Gland ....................................... 54
Temporomandibular Joint .................... 57
Movements of the Mandible ................ 59
Maxillary Artery .................................. 60
Maxillary Nerve ................................... 61
Mandibular Nerve ................................ 62
Pterygopalatine Ganglion..................... 63
Submandibular Gland .......................... 64
Lingual Nerve ...................................... 67
Nasal Cavity: Relations, Openings &
Branches ............................................... 68
Tongue: Features & Muscles ............... 71
Innervation of the Tongue.................... 73
Constrictor Muscles of Pharynx........... 74
Nasopharynx ........................................ 75
Mechanism of Swallowing .................. 77

1
Sternocleidomastoid Muscle
The sternocleidomastoid is 1 of the 2 large, supf muscles of the neck

Origin
sternal head • tendinous
• arises from superolat part of front of manubrium sterni
clavicular head • musculotendinous
• arises from med 1/3 of upper surface of clavicle

Insertion
It is inserted by:
1. a tendon into mastoid process of the temporal bone
2. a thin aponeurosis into lat part of sup nuchal line of occipital bone

Nerve Supply
spinal part of accessory n motor
ventral rami of C2 & C3 sensory (proprioceptive)

Blood Supply
by branches from occipital artery

Actions
When both muscles contract: 1. extend head at atlanto-occipital jt
2. flex cervical part of vertebral column
When 1 muscle contracts: 1. tilt the head towards the shoulder
2. rotates head so that the face looks
upwards on the oppo side
If the head is fixed, the 2 muscles can also act as accessory muscles of inspiration

2
Relations
Supf 1. skin
2. fascia & platysma
3. ext jugular vein (EJV)
4. great auricular, tnvs cut & med supraclavicular nerves
5. supf cervical LN along EJV
6. parotid gland
Deep 1. carotid sheath & its contents: common & ICA, IJV & vagus n
2. muscles: sternohyoid, sternothyroid, omohyoid, scaleni ant, med & post
levator scapulae, splenius capitis & post belly of digastric
3. besides common carotid art (CCA) & int carotid art (ICA)
there are also 1. ext carotid art (ECA)
2. occipital art
3. subclavian art & suprascapular art
4. besides int jugular vein (IJV), there are also 1. ant jugular vein
2. facial vein
3. lingual vein
5. besides vagus nerve there also: 1. accessory nerve
2.cervical plexus
3. upper part of brachial plexus
4. phrenic n & ansa cervicalis
6. deep cervical LN

Clinical Notes
1. the sternocleidomastoid divides the neck into ant & post triangles
2. congenital torticollis
3. spasmodic torticollis

3
Scalenus Anterior Muscles
The scalenus anterior is an impt muscle of the lower part of the neck
because of its relations with the impt structures in that region

Origin
from the ant tubercles of the tnvs processes of CV3, 4, 5 & 6

Insertion
The fibres are inserted into
1. scalene tubercle on inner border of 1st rib
2. ridge on upper surface of 1st rib

Innervation
from ventral rami of C4, 5 & 6

Action
1. assists elevating 1st rib
2. when acting from below, it laterally flexes & rotates cervical part of vertebral
column

Relations
Anteriorly Posteriorly Medially Laterally
1. prevertebral 1. subclavian art 1. vertebral art & v 1. roots of brachial
layer of deep 2. brachial plexus 2. inf thyroid art plexus
cervical fascia 3. cervical dome 3. thyrocervical 2. subclavian art
2. phrenic n of pleura trunk 3. roots of phrenic n
3. supf cervical & 4. symp trunk
suprascapular art 5. on the left side,
4. IJV & subclavian thoracic duct
vein

4
Anterior Triangle of the Neck
The sternocleidomastoid musc divides the neck into an ant triangle & a post triangle

Boundaries
Anteriorly ant median line of neck
Posteriorly ant border of sternocleidomastoid
Superiorly inf border of mandible & a line drawn from angle of mandible to
mastoid process
Inferiorly the apex of the triangle lies at the manubrium sterni

Subdivision
It is subdivided by the digastric & sup belly of omohyoid into
a. submental
b. digastric
c. carotid
d. muscular triangles

a) Submental Triangle
base hyoid core
on each side ant belly of digastric

b) Digastric Triangle
anteroinferiorly ant belly of digastric
posteroinferiorly post belly of digastric
superiorly (base) inf border of mandible

c) Carotid Triangle
anteriorly sup belly of omohyoid
posteriorly ant border of sternocleidomastoid
superiorly post belly of digastric

d) Muscular Triangle
anteriorly ant median line of neck
posterosuperiorly sup belly of omohyoid
posteriorinferiorly ant border of sternocleidomastoid

Roof
The roof is formed by 1. skin
2. fascia
3. platysma

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Floor
Triangle formed by
Submental mylohyoid muscles
Digastric 1. mylohyoid
2. hyoglossus
Carotid 1. thyrohyoid
2. hyoglossus
3. inf & middle constrictors of pharynx
Muscular 1. sternohyoid
2. sternothyroid
3. thyrohyoid
ie. infrahyoid muscles

Contents
Triangle Contents
Submental 1. LN
2. veins
Digastric 1. submandibular gld
2. facial art & vein
3. portions of parotid gld
4. ECA
situated more deeply
5. ICA
6. IJV
7. glossopharyngeal n
8. vagus n
Carotid 1. CCA, ECA & ICA (more deeply)
2. branches of ECA
3. IJV & some of its tributaries
4. portions of X, XI & XII cranial n
5. larynx & pharynx
6. int & ext laryngeal n
Muscular 1. thyroid gld
2. trachea & larynx
3. esophagus

6
Posterior Triangle of the Neck
• The sternocleidomastoid muscle divides the neck into an ant triangle & a post
triangle
• The post triangle is situated bhd the muscle

Boundaries
Anteriorly post border of sternocleidomastoid
Posteriorly ant border of trapezius
Inferiorly upper surface of middle 1/3 of clavicle
Superiorly apex lies on the sup nuchal line line where
the sternocleidomastoid & trapezius meet

Subdivisions
The inf belly of the omohyoid divides it into
1. large upper part: occipital triangle
2. smaller lower part: supraclavicular (subclavian) triangle

Roof
The roof is formed by 1. skin
2. fascia
3. platysma
The fascia is pierced by the EJV & supraclavicular n

Floor
The floor is formed by 1. semispinalis capitis (inconstant)
2. splenius capitis
3. levator scapulae
4. scalenus post
5. scalenus medius
6. scalenus ant (inconstant)
7. 1st digitations of serratus ant
These muscles are covered by prevertebral layer of fascia

7
Contents
Occipital 1. spinal part of accessory n
Triangle 2. 4 cutaneous branches of cervical plexus
a. lesser occipital
b. great auricular
c. tnvs cervical
d. 3 supraclavicular n
3. dorsal scapular n (to rhomboids)
4. upper part of brachial plexus
5. tnvs cervical art & vein
6. occipital art from ECA
7. lymph nodes : along post border of sternocleidomastoid
: supraclavicular nodes
: occipital nodes
Subclavian 1. 3 trunks of brachial plexus
Triangle 2. long thoracic n (to serratus ant)
3. nerve to subclavius
4. suprascapular n
5. 3rd part of subclavian art & subclavian vein
6. suprascapular art & vein
7. tnvs cervical art & vein
8. lower part of EJV
9. a few supraclavicular LN

Clinical Notes
1. enlargement of supraclavicular LN due to malignancies etc
2. brachial plexus can be anaesthetized by injection of local anaesthetic btw 1st rib &
skin above clavicle

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Thyroid Gland
The thyroid gld is an endocrine organ which regulates basal metabolic rate &
stimulates growth

Shape
roughly H-shaped

Parts
• 2 lobes: R & L
• isthmus, which connects the lobes
• sometimes a pyramidal lobe is present

Position
• The gld lies at the level of CV5, 6, 7
• each lobe extends from middle of thyroid cartilage to 4th or 5th tracheal ring
• isthmus extends from 2nd to 3rd tracheal ring

Capsules (Coverings)
fibrous capsules adherent to underlying gld
false capsules • ext to fibrous capsule
• derived from pretracheal layer of deep cervical fascia
• form suspensory lig to anchor the gld to the thyroid &
cricoid cartilages & to the trachea

Relations of the Lobes

Anterolat 1. sternothyroid
2. sternohyoid
3. sup belly of omohyoid
4. ant border of sternocleidomastoid
Posterolat carotid sheath & its contents: 1. CCA
2. IJV
3. vagus n
Medially 1. larynx
2. trachea
3. inf constrictor of pharynx
4. esophagus
Associated with these structures are
5. cricothyroid
6. ext laryngeal n
7. recurrent laryngeal n (in groove btw trachea & esophagus)
Post border of the 1. sup & inf parathyroid glds
2 lobes is rounded 2. anastomosis btw sup & inf thyroid art
& related to 3. on the L side, thoracic duct

9
Relations of the Isthmus
Anteriorly 1. sternothyroid
2. sternohyoid
3. ant jugular vein
4. fascia & skin
Posteriorly 2nd, 3rd & 4th tracheal rings
Superiorly terminal branches of the sup thyroid art
anastomose along its upper border

Arterial Supply
sup thyroid art from ECA
inf thyroid art from thyrocervical trunk
thyroidea ima from brachiocephalic art / arch of aorta

Venous Drainage
sup thyroid vein into IJV
middle thyroid vein into IJV
inf thyroid vein anastomose with L brachiocephalic vein

Lymphatic Drainage
The lymphatics follow the arteries & drain mainly into:
1. deep cervical LN
2. a few lymph vsls pass to paratracheal nodes

Nerve Supply
• nerves derived mainly from middle cervical ganglion
• also partly from sup & inf cervical ganglia
• the nerves are vasoconstrictor

Clinical Notes
1. goitre = any enlargement of thyroid gld
Causes: eg iodine def
puberty (puberty goitre)
tumours, etc
2. hyperthyroidism
hypothyroidism
3. because of the relations of the thyroid to impt structures
a. thyroidectomy may cause damage to the structures
b. enlargement of the gld may displace & compress the structures
eg trachea

10
Common Carotid Artery
Origin
Right CCA • branch of brachiocephalic art (trunk)
• begins in neck bhd R sternoclavicular jt
Left CCA • branch of aortic arch
• begins in thorax & passes bhd L
sternoclavicular jt

Course
• runs in carotid sheath along with IJV & vagus n
• passes upwards & backwards in the neck,
from sternoclavicular jt to upper border of thyroid cartilage
• ends by dividing into ECA & ICA (no other named branches)

Special Features
carotid sinus • localised dilatation at terminal part of CCA (or beginning of ICA)
• innervated by glossopharyngeal & symp n
• act as baroreceptor to regulate bld pressure
carotid body • small reddish-brown structure situated bhd bifurcation of CCA
• innervated mainly by glossopharyngeal n
• acts as chemoreceptor
ie. respond to changes in concn of O2 & CO2 in bld

Relations
Anterolat 1. skin, supf fascia, platysma, investing layer of deep cervical fascia
2. sternocleidomastoid overlaps it
3. sternohyoid
4. sternothyroid
5. sup belly of omohyoid
Embedded in ant wall of carotid sheath
6. descendens hypoglossi
7. ansa cervicalis
Crossing the art,
8. sup & middle thyroid veins
9. ant jugular veins
Posteriorly 1. tnvs processes of lower 4 cervical vertebral
2. longus capitis & longus colli
3. origin of scalenus ant
4. symp trunk
in the lower part of the neck
5. vertebral vsls
6. inf thyroid art
On the L side
7. thoracic duct
Bhd the termination of CCA = carotid body

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 Medially 1. larynx & pharynx
2. trachea
3. esophagus
4. lobe of thyroid gld
5. inf thyroid gld
6. recurrent laryngeal n
Laterally 1. IJV
2. vagus lies posterolat

Surface Anatomy
pt A: sternoclavicular jt
pt B: ant border of sternocleidomastoid at level of upper border of thyroid cartilage
Joining these 2 pts will surface mark the art in the neck

Clinical Notes
1. ligature of the CCA on 1 side
collateral circulation is est btw
1) sup & inf thyroid art (inf thyroid & deep cervical from subclavian)
2) desc branches of occipital & deep cervical art
3) vertebral art
Note: (1) and (2) are outside cranial cavity
(3) is inside cranial cavity
2. bifurcation of CCA: carotid pulse may be felt
3. the art can be compressed on ant tubercle of tnvs process of CV6 (carotid
tubercle)

12
External Carotid Artery
The ECA is one of the 2 terminal branches of the CCA
& is the chief art of supply to ant structures in the neck & face

Origin
• begins in carotid triangle\
• at level of upper border of thyroid cartilage (ie. btw CV3 & 4)

Course
• runs upwards, slightly backwards & laterally
• enters substance of parotid gld
• terminates bhd neck of mandible by dividing into the
maxillary & supf temporal art
Note: at first it lies medial to ICA.
It then passes backwards & laterally to lie lat to ICA

Branches
There are 8 branches
1. sup thyroid
2. asc pharyngeal
3. lingual
4. facial
5. occipital
6. post auricular
7. supf temporal
8. maxillary

13
Relations
Anterolat (Supf) 1. sternocleidomastoid overlaps it at its beginning
Above this level, it is relatively supf & is covered by
2. skin & supf fascia
3. cervical branch of facial n
4. tnvs cutaneous n
5. investing layer of deep cervical fascia
It is crossed by
6. hypoglossal n
7. facial & lingual veins
8. post belly of digastric
9. stylohyoid muscles
Within parotid gld, it is crossed by
10. facial n & retromandibular vein
Note: The IJV first lies lat to the art, then post to it
Medially 1. wall of pharynx
2. styloid process
3. ICA
Passing btw the ECA & ICA
4. stylopharyngeus
5. glossopharyngeal n
6. pharyngeal branch of vagus n
7. portion of parotid gld

Surface Anatomy
pt A: pt on ant border of sternocleidomastoid
at level of upper border of thyroid cartilage
pt B: pt bhd neck of mandible
midway btw mastoid process & angle of mandible
Joining these 2 pts gives the surface marking of ECA

Clinical Notes
Ligature of art of 1 side
- collateral circulation is maintained btw the branches of the ECA
with those of the oppo side

14
Internal Carotid Artery (Cervical Part)
• The ICA is one of the 2 terminal branches of the CCA
• It is the principal art to the brain & eye
• Its course is divided into 4 parts
a) cervical part
b) petrous part
c) cavernous part
d) cerebral part
The cervical part is discussed here

Origin
• begins in the carotid triangle
• at level of upper border of thyroid cartilage (ie btw CV3 & 4)

Course
• enclosed in carotid sheath tog with IJV & vagus n
• asc vertically in the neck to lower end of carotid canal in petrous temporal bone
• lower part (in carotid triangle) is comparatively supf
• after ascending deep to post belly of digastric, it lies deep to parotid gld, styloid
process & many other structures
• it does not give any named branches in the neck

Special Features
The ICA may present 2 structures at its commencement
carotid sinus • localised dilatation at terminal part of CCA (or beginning of ICA)
• innervated by glossopharyngeal & symp n
• act as baroreceptor (regulate bld pressure)
carotid body • small reddish-brown structure situated bhd bifurcation of CCA
• innervated mainly by glossopharyngeal n
• acts as chemoreceptor (detect changes in bld O2 & CO2)

15
Relations
Anterolat Below digastric
(Supf) 1. skin, supf fascia, platysma, investing layer of deep cervical fasica
2. tnvs cutaneous n
3. ant border of sternocleidomastoid
4. lingual & facial n
5. hypoglossal n & its descending branch
6. occipital art
Above digastric
7. post auricular art
8. stylohyoid & stylopharyngeus
9. styloid process
10. glossopharyngeal n
11. pharyngeal branch of vagus n
12. parotid gld & its contents : facial n
: retromandibular vein
: ECA
Posteriorly 1. sup laryngeal n
2. cervical part of sym trunk & sup cervical ganglion
3. longus capitis & prevertebral layer of deep cervical fascia
4. tnvs processes of upper 3 cervical vertebrae
Medially 1. pharynx
2. sup laryngeal n
3. ext & int laryngeal n
4. asc pharyngeal art
Laterally 1. IJV
2. vagus

Surface Anatomy
pt 1: ant border of sternocleidomastoid at level of upper border of thyroid cartilage
pt 2: post border of condyle of mandible
Joining these 2 pts gives the surface marking of the ICA

Clinical Notes
atherosclerosis causes 1. impairment of vision
2. cerebral disorders

16
Subclavian Artery
This is the principal artery of the upper limb
but also supplies part of the neck & brain through its branches

Origin
R subclavian art • arises from brachiocephalic art (trunk)
• bhd R sternoclavicular jt
L subclavian art • arises from arch of aorta bhd L CCA
• asc to back of L sternoclavicular jt

Course
For descriptive purposes, the subclavian art is divided into 3 parts by the presence of
the scalenus ant
1st Part arches upwards & lat from bhd sternoclavicular jt to med border of
scalenus ant
nd
2 Part lies bhd scalenus ant muscle
3rd Part • extends from lat border of scalenus ant to outer border of 1st rib
where it continues as axillary art
• supf & can be compressed against 1st rib

Branches
1st Part 1. vertebral art
2. thyrocervical trunk
a) inf thyroid
b) tnvs cervical
c) suprascapular
3. int thoracic art
2nd Part costocervical trunk
a) sup IC art
b) deep cervical art
3rd Part descending (dorsal) scapular art

Relations of 1st Part

Anteriorly From med to lat
1. CCA
2. ansa subclavia
3. vagus n
4. IJV
5. vertebral veins
6. on L side = thoracic duct
In addition
7. cardiac branches of vagus & symp n
Posteriorly 1. dome of cervical pleura & suprapleural mbm
2. apex of lung
3. ansa subclavia which encircles the art
4. symp trunk & inf cervical ganglion
5. on the R side = R recurrent laryngeal n

17
Relations of the 2nd Part
Anteriorly 1. scalenus ant
2. sternocleidomastoid
3. subclavian vein (sep by scalenus ant)
4. on R side = R phrenic n
Posteriorly 1. dome of cervical pleura & suprapleural mbm
2. apex of lung
3. scalenus medius

Relations of 3rd Part

Anteriorly 1. skin, supf fascia, platysma, investing layer of deep cervical fascia
2. supraclavicular n
3. EJV & its tributaries : ant jugular vein
: tnvs cervical
: suprascapular
4. suprascapular art
5. n to subclavius
6. clavicle & subclavius
Posteriorly 1. scalenus medius
2. lower trunk of brachial plexus
Superiorly upper & middle trunks of brachial plexus
Inferiorly upper surface of 1st rib

Surface Anatomy
pt 1: on sternoclavicular jt
pt 2: at middle of lower border of clavicle
The art is marked by a curved line,
convex upwards to abt 2 cm above the clavicle, joining the 2 pts

Clinical Notes
1. 3rd part of subclavian art may be compressed against 1st rib to stop bleeding in
upper arm
2. aneurysms may form in 3rd part of artery
- exert pressure on brachial plexus & results in
pain, weakness & numbness in upper limb
3. cervical rib – art is kinked as it passes over rib, causing occlusion

18
Internal Jugular Veins
The IJV drains the brain, neck & face

Origin
• begins at jugular foramen at base of skull
• it is a continuation of the sigmoid sinus

Course
• descends in carotid sheath
• passes downwards & anteriorly
• ends bhd med end of clavicle by joining with subclavian vein
to form brachiocephalic vein

Special Features
1. sup bulb: dilatation at is origin
2. inf bulb: dilatation near its termination
3. The vein possess 1 bicuspid valve directly above inf bulb

Relations
Anterolat 1. skin, supf fascia, platysma, investing layer of deep cervical fascia
2. sternocleidomastoid
3. post belly of digastric
4. parotid salivary gld sep from it by styloid process & stylopharyngeus
Its lower part is covered by
5. sternohyoid, sternothyroid & omohyoid
Crossing the vein
6. ansa cervicalis
7. stylohyoid
8. post auricular & occipital art
9. spinal part of accessory n
Also supf are
10. facial n
11. ant jugular vein
12. The deep cervical LN run alongside the IJV
Posteriorly 1. tnvs processes of cervical vertebrae
2. levator scapulae
3. scalenus ant & medius
4. cervical plexus
5. phrenic n
6. thyrocervical trunk
7. vertebral vein
8. 1st part of subclavian art
9. dome of cervical pleura
10. on the L = thoracic duct
Medially Below,
1. vagus n
2. CCA
At base of skull
3. ICA
4. 9th, 10th, 11th & 12th cranial n

19
Tributaries
1. inf petrosal sinus
2. facial vein
3. lingual vein
4. pharyngeal veins
5. sup thyroid vein
6. middle thyroid vein
7. sometimes, occipital vein
Note: Thoracic duct opens into angle of union btw left IJV & L subclavian vein
The right lymphatic duct opens similarly on the r side

Surface Anatomy
pt 1: on neck, med to lobule of ear
pt 2: at med end of clavicle
Joining these 2 pts will surface mark the IJV

Clinical Notes
1. In congestive heart failure or any disease where venous pressure is raised, the IJV
is markedly dilated, engorged
2. Deep cervical LN lie along the IJV.
In malignancies involving these nodes, the vein is usu removed tog with the nodes
in a surgical procedure called block dissection of the cervical nodes

20
Cervical Plexus
The cervical plexus supplies the skin at the back of the head, the neck & shoulder as
well as certain muscles of the neck tog with the diaphragm

Formation
• by ventral rami of C1 to C4
• the rami are joined by connecting branches to form a series of 3 loops from which
the branches arise

Position & Relations

Anteriorly 1. It is covered ant by prevertebral layer of deep cervical fascia
It is also related to
2. IJV in carotid sheath
3. sternocleidomastoid
Posteriorly It lies in front of the origins of
1. levator scapulae
2. scalenus medius

Branches
Supf (Cut) Branches 1. Lesser occipital (C2)
2. great auricular (C2, 3)
3. tnvs cut (cervical) (C2, 3)
4. med, intermediate & lat supraclavicular (C3, 4)
The cutaneous branches all emerge near middle of post border
of sternocleidomastoid
Deep Branches Communicating Branches
1. Each of the 4 rami receive GRC from the sup cervical
ganglion of the symp trunk
2. branch from C1 to hypoglossal n
3. other branches to vagus & accessory n
Muscular Branches to:
1. prevertebral muscles
2. sternocleidomastoid
3. levator scapulae
4. scaleni ant, medius & post
5. trapezius
It also supplies:
6. diaphragm via phrenic n
7. infrahyoid muscles (except thyrohyoid) via ansa cervicalis
Ansa cervicalis
• lies supf to (or in the substance of) the carotid sheath
• formed by 1. desc branch of hypoglossal n (C1)
2. descending cervical n (C2, 3)
which unite to form a loop
• supply omohyoid, sternohyoid & sternothyroid
(Thyrohyoid is supplied directly via C1 fibres within
hypoglossal n)

21
Phrenic Nerve (Cervical Part)
• The phrenic n is a mixed n carrying motor fibres to the diaphragm & sensory
fibres from the pleura, pericardium, peritoneum & diaphragm
• It also carries symp fibres
• It is the only motor supply of the diaphragm

Origin
• from C3, C4 & C5 (mainly C4)
• at lat border of scalenus ant at level of circoid cartilage
• The contribution from C5 may come via n to subclavius, in which case it is called
accessory phrenic n

Course
• runs downwards vertically on ant surface of scalenus ant (bhd prevertebral fascia)
• since scalenus ant is oblique, phrenic n crosses it from lat to med border
• crosses int thoracic art from lat to med side
• enters thorax by passing in front of subclavian art & bhd beginning of
brachiocephalic vein
• it does not give any branches in the neck

Relations
Anteriorly 1. prevertebral layer of deep fascia
2. IJV
3. supf cervical & suprascapular art
4. beginning of brachiocephalic vein
5. on the L: thoracic duct
Posteriorly 1. scalenus ant
2. subclavian art
3. cervical dome of pleura

Surface Anatomy
pt 1: on side of neck at level of upper border of thyroid cartilage &
∼ 3.5 cm from median plane
pt 2: med end of clavicle
Joining these 2 pts will surface mark the course of the phrenic n in the neck

Clinical Notes
surgical interruption of the phrenic n on the scalenus ant is sometimes perfomed to aid
in collapse of a lung
ie. diaphragm on affected side is paralysed & is therefore elevated, leading to
collapse of the lung
This gives rest to a diseased lung & promotes healing

22
Cervical Part of Sympathetic trunk
• This is a ganglionated chain located one on each side of the cervical part of the
vertebral column
• From it comes the symp supply to the various structures of the head & neck

Formation
• by fibres (PreGN) arising from segments T1 to T4 of spinal cord
• these fibres pass to thoracic part of symp trunk & then ascend into the neck

Extent
• upwards to base of skull
• downwards to neck of 1st rib where it becomes continuous with thoracic part of
symp trunk

Relations
It is prevertebral & is related to
Anteriorly 1. carotid sheath
2. CCA & ICA
3. inf thyroid art
Posteriorly 1. prevertebral fascia
2. longus capitis & cervicis
3. tnvs processes of lower 6 CV

23
Ganglia
• There are 3 ganglia: sup, middle & inf
• The asc PreGN fibres synapse in these ganglia,
from which PGN fibres arise to supply the SM, BV & glds of the head & neck
Cervical Remarks Branches
Ganglion
Superior • largest of the 3 ganglia 1. GRC to C1 to C4 (ventral rami)
• formed by the fusion of the upper 2. branches to 9th , 10th & 12th cranial n
4 ganglia 3. int carotid n  int carotid plexus
• lies just below skull at level of 4. arterial branches to CCA & ECA
CV1 to CV3 bhd ICA & in front 5. pharyngeal branches
of longus capitis  pharyngeal plexus (with branches
of 9th & 10th cn)
6. sup cervical branch
 cardiac plexus in thorax
Middle • very small 1. GRC to venral rami of C5 & C6
• formed by fusion of 5th & 6th 2. thyroid branches  thyroid gld
cervical ganglia 3. middle cardiac branch
• lies in lower part of neck in front  cardiac plexus in thorax
of CV6 above arch formed by inf
thyroid art
Inferior • rather large, irregular & star- 1. GRC to ant rami of C7 & C8
shaped 2. arterial branches
• formed by fusion of 7th & 8th  subclavian & vertebral art
cervical ganglia, & often with 1st 3. inf cardiac branch
thoracic ganglia  cardiac plexus in thorax
 stellate ganglion
• lies btw tnvs process of CV7 &
neck of 1st rib bhd vertebral art

Clinical Notes
1. injury to cervical part of symp trunk produced Horner’s syndrome
2. stellate ganglion can be blocked by anesthetic

24
Trachea (Cervical Part)
• The trachea is a mobile, non-collapsible tube forming the beginning of the lower
resp passages
• It is kept potent by anterolat C-shaped cartilaginous rings
• Its post membranous part permits expansion of the esophagus during passage of
food

Origin
begins at lower border of criccoid cartilage of larynx (at level of CV6) in the middline

Course
• runs downwards & slightly backwards in the midline
• enters thorax in median plane

Relations
Anteriorly 1. skin & fascia
2. isthmus of thyroid gld (in front of 2nd, 3rd & 4th rings)
3. inf thyroid veins
4. jugular arch
5. thyroidea ima art (if present)
6. sternothyroids & sternohyoids
7. L brachiocephalic vein in the child
Posteriorly 1. R & L recurrent laryngeal n
2. esophagus
3. vertebral column & some prevertebral muscles
Laterally 1. lobes of thyroid gld
(on each side) 2. carotid sheath & CCA

Blood Supply
mianly from inf thyroid arteries

Venous Drainage
veins drain into L brachiocephalic vein

Lymphatic Drainage
Lymphatics pass to 1. pretracheal nodes
2. paratracheal nodes

Nerve Supply
1. psymp: vagus & recurrent laryngeal n
 sensory & secretomotor to mucous mbm
motor to trachealis muscle
2. symp: from middle cervical ganglion of symp trunks
 vasomotor

25
Clinical Notes
1. trachea may be compressed by pathological enlargement of thyroid, thymus, LN
& aortic arch
2. tracheostomy is usu done after cutting the isthmus of thyroid gld

26
Lymphatic Drainage of the Head & Neck
The lymphatic system of the head & neck consists of 1. LN
2. lymph vsls

Lymph Nodes
• The lymph nodes of the head & neck are made up of a no. of peripheral gps, & a
terminal gp
• The terminal gp receives all the lymphatics of the head & neck,
either directly or indirectly via one of the peripheral gps

Peripheral Groups of Lymph Nodes

These are arranged in 2 gps: supf & deep
a) The supf gp consist of
Nodes Remarks
1 occipital nodes • located over occipital bone at apex of post triangle of neck
• receive lymph from back of scalp
• efferents to deep cervical nodes
2 retro-auricular • located over lat surface of mastoid process of temporal
(mastoid) nodes bone
• receive lymph from scalp above auricle &
from post wall of ext auditory meatus
• efferents to deep cervical nodes
3 parotid nodes • located on / within parotid gld
• receive lymph from scalp, auricle, face, ext acoustic meatus
& middle ear
• efferents to deep cervical LN
4 buccal nodes • located over buccinator muscle close to facial vein
• lie along course of lymph vsls
ie receives from several nodes
• efferents to submandibular cervical LN
5 submandibular • located on surface of submandibular gld
nodes • receive lymph from wide area
• efferents to deep cervical nodes
6 submental • located in submental triangle btw ant bellies of digastric
nodes • receive lymphfrom lower lip, tongue & supf neck
• efferent to submandibular & deep cervical nodes

- These 6 gps of LN form a collar at the jn of the head with the neck called
pericervical collar
- The supf tissues of the head & neck drain into these nodes, as well as 2 other gps
7 ant cervical • located along course of ant jugular vein
nodes • receive lymph from supf tissue of front of neck
• efferent to deep cervical nodes
8 supf cervical • located along the course of EJV
nodes • receive lymph from small part of face & ext ear
• efferents to deep cervical nodes

27
b) The deep gp of peripheral LN are:
9 retropharyngeal fd in interval btw pharyngeal wall & prevertebral fascia
nodes ie retropharyngeal space
10 laryngeal nodes fd in front of larynx on cricothyroid lig
11 paratracheal nodes fd lat to trachea
12 pretracheal nodes fd in front of trachea

Terminal Group of Lymph Nodes

• These are the deep cervical nodes
• fd in a chain along the course of IJV
• embedded in fascia of carotid sheath
• receive all lymph of head & neck
• efferents join to form jugular lymph trunks which drains into thoracic duct or R
lymphatic duct
Note: 2 of the nodes are referred to clinically: 1. jugulo-digastric node
2. jugulo-omohyoid node

Lymph Vessels
supf vsls  follow supf veins
deep vsls  follow arteries & sometimes deep veins

Clinical Notes
1. enlargement of nodes may indicate infection of its area of drainage
2. spread of cancer through the lymphatics
3. block dissection of cervical nodes
ie removal of cervical nodes, IJV, submandibular gld & fasica
may be performed in some cases of cancer

28
Scalp
Soft tissues covering the cranial vault form the scalp

Extent
Anteriorly supraorbital margins
Posteriorly ext occipital protuberance & sup nuchal lines
Laterally sup temporal lines on each side
Hairline does not correspond to boundaries of scalp
- hair is deficient over front part of scalp
- hair overlaps upper part of back of neck

Structure
The scalp consists of 5 layers, the 1st 3 of which are intimately connected & move as a
unit. The layers are:
Skin thick, hair-bearing & contains sebaceous glds
Connective tissue fibro-fatty layer beneath the skin containing anastomoses of
arteries & veins
Aponeurosis of
occipito-frontalis
muscles
Loose areolar tissue • lies below the aponeurosis in the subaponeurotic space
• contains emissary veins
Pericranium periosteum covering outer surface of skull bones

Blood Supply
The scalp has a very rich bld supply  small cuts tend to bleed profusely
In front of the auricle, it is supplied from before backwards by
1 supratrochlear branches of ophthalmic art (br of ICA)
2 supraorbital branches of ophthalmic art (br of ICA)
3 supf temporal terminal branch of ECA
Behind the auricle, it is supplied from before backwards by:
4 post auricular branches of ECA
5 occipital branches of ECA

Venous Drainage
1. supratrochlear – unite at med margin of orbit to form facial vein
2. supraorbital – unite at med margin of orbit to from facial vein
3. supf temporal vein
4. post auricular vein
5. occipital vein  suboccipital venous plexuses
The veins of the scalp anastomose with diploic veins
They are connected to the intracranial venous sinuses by emissary veins

Lymphatic Drainage
part of scalp drains into
ant part of scalp pre-auricular (parotid) nodes
post part of scalp mastoid & occipital nodes

29
Nerve Supply
a) Sensory Innervation
From ant to post by branches of
1. ophthalmic n – from 5th cranial n
2. maxillary n – from 5th cranial n
3. mandibular n – from 5th cranial n
4. cervical plexus
5. dorsal rami of cervical spinal n
b) Motor Innervation
branches of facial n - temporal branch to frontal belly
- post auricular branch to occipital belly

Clinical Notes
1. scalp bleeds profusely when injured due to rich bld supply
2. emissary veins in loose areolar tissue (subaponeurotic) are inv in spread of
infection from scalp to intracranial regions
Thus the area is called ‘danger area’

30
Facial Artery
The facial artery is the chief artery of the face

Origin
• branch of ECA
• given off in carotid triangle in the neck

Course
• brief course in the neck
• winds round lower border of mandible at ant margin of masseter
• proceeds upwards & forwards on the face
• ends at med angle of the eye where it anastomoses with branches of ophthalmic
art
• The facial art is very tortuous & takes part in numerous anastomoses, including
some across median plane
• Tortuous course permits free movement of the mandible, lips & cheeks

Venous Drainage
Facial vein - connects to cavernous sinus & pterygoid plexus
Thus spread of infection from face into cranial cavity

Branches
In the neck: 1. asc palatine art
2. tonsillar branch
3. glandular branch to submandibular gld
In the face it supplies the lips & ext nose via: 1. submental art
2. inf labial art
3. sup labial art
4. lat nasal art

Clinical Notes
There.is rich anastomosis
 collateral circulation can be est after ligature of the CCA or ECA on 1 side

Other arteries supplying the face

1 supf temporal art from ECA
2 tnvs facial art from supf temporal art
3 supraorbital from ophthalmic art
4 supratrochlear from ophthalmic art

31
Facial Nerve
The facial n is the 7th cranial nerve.
It is also the nerve to the 2nd branchial arch
It is 1. motor to the face
2. secretomotor to submandibular & sublingual salivary glds & lacrimal glds
3. special sensory (taste) to ant 2/3 of the tongue

Nuclei & Functional Components

1 motor nucleus SVE
2 sup salivatory nucleus GVE
3 lacrimatory nucleus GVE
4 nucleus of solitary tract SVA
5 spinal nucleus of V GSA

Course
Intracranial Course • starts off as 2 roots - motor
- sensory (nervus-intermedius)
& secretomotor
• leave brain at lower border of pons
• enter int acoustic meatus
• enter facial canal of temporal bone
- Above promontory of med wall of middle ear, it forms
geniculate ganglion (containing cells of taste fibres)
• emerges from skull at stylomastoid foramen
Extracranial Course • crosses laterally the base of styloid process
• enters posteromed surface of parotid gld
• runs forward within the gld, supf to retromandibular vein
& ECA
• bhd neck of mandible it divides into its 5 terminal
branches, which emerge at the ant border of the gld

Branches
a) Intracranial Branches
within facial canal: 1. greater petrosal n
2. n to stapedius
3. chorda tympani (joins lingual n)
b) Extracranial Branches
At exit from stylomastoid formen: 1. post auricular
2. muscular branches to digastric &
stylohyoid

32
c) Terminal Branches
1. temporal
2. zygomatic
3. buccal
4. mandibular
5. cervical
These arise in the substance of the parotid gld & emege from its ant border
The facial n supplies all the muscles of facial expression
It does not supply the skin
d) Communicating Branches
- communicate with adj cranial & spinal n

Surface Anatomy
pt 1: at middle of ant border of mastoid process
= position of stylomastoid foramen
pt 2: bhd neck of mandible
= pt of division into terminal branches
Joining these 2 pts will give extracranial course of facial n

Clinical Notes
1. Lesions of the facial n below / at the level of the motor nucleus results in
lower motor-neuron lesion
- Possible causes: 1. infection of middle ear
2. surgery, etc
- Result: paralysis of entire facial musculature on affected side
- Features : displacement of mouth accompanied by drooping
: ptosis, & inability to close eyes
: no wrinkles on forehead
2. Lesions of the facial n above level of the motor nucleus results in
upper motor-neuron lesion
- Possible causes: 1. tumours
2. surgery, etc
- Result : Lower half of face of oppo side paralysed
: orbicularis oculi & frontalis muscles spared because
they are controlled by fibres from both sides of cerebral cortex
- Features : displacement & drooping of mouth contralaterally
However the patient is able to wrinkle his forehead

Distribution of Facial Nerve

4 modalities carried by nerve
Motor 1. to muscles of facial expression
2. stylohyoid, digastric
3. stapedius
Special Senses taste fibres to ant 2/3 of tongue
Pysmp secretomotor to submandibular, sublingual glds
lacrimal gld
parotid gld
Sensory small area of ext meatus, auricle

33
Dura Mater of the Brain
• The dura mater is the outermost, thickest & toughest mbm covering the brain
• It is continuous with the dura of the spinal cord

Layers of the Dura Mater

It has 2 layers
1. outer layer / endosteal layer – serves as an int periosteum to the cranial bones
2. inner layer / meningeal layer – provides the protective mbm to the brain
The 2 layers are fused except at places where cranial venous sinuses are enclosed btw
them

Processes of the Dura Mater

The meningeal layer sends 4 folds internally which divide the cranial cavity into
many freely communicating compartments housing different parts of the brain
1 Falx Cerebri • large, sickle-shaped fold
• occupies median longitudinal fissure btw the 2 cerebral
hemispheres
• attachments: anteriorly to crista galli
posteriorly to tentorium cerebelli
• upper convex border contains sup sagittal sinus
lower concave border contains inf sagittal sinus
2 Tentorium • tent-shaped fold forming roof of post cranial fossa
Cerebelli • supports occipital lobe above & sep it from cerebellum below
• anteriorly it shows as gap
 tentorial notch, for passage of the midbrain
Thus, it has 2 borders:
1. ant free border forming tentorial notch
which is attached on both sides to ant clinoid process
2. outer attached border which is attached to
post clinoid process
• outer attached border encloses sup petrosal & tnvs sinuses
upper surface encloses straight sinus
3 Falx small sickle-shaped fold lying below tentorium cerebelli
Cerebelli
4 Diaphragma small circular horiz fold forming roof of hypophyseal fossa
Sellae

Blood Supply
• outer layer is richly vascular
inner layer is more fibrous & requires little blood supply
• The dura is supplied by numerous meningeal branches from
1. ICA
2. maxillary asc pharyngeal art
3. occipital art
4. vertebral art
• The most impt is middle meningeal art

34
Venous Drainage
by meningeal veins into pterygoid plexus of veins or sphenoparietal sinus

Nerve Supply
The dura is supplied by branches of the trigeminal & cervical nerves
ant cranial fossa ophthalmic n
middle cranial fossa maxillary & mandibular n
post cranial fossa branches of vagus & hypoglossal n
as well as branches from C1 to C3
The nerve supply is
a) sensory to the dura
b) autonomic to the BV

Clinical Notes
1. headache usu implicates the dura & the structures contained in it because the brain
itself is normally quite insensitive
2. intracranial hemorrhages

35
Cranial Fossae
• interior of the base of the skull is divided into 3 cranial fossae:
anterior cranial fossa
middle cranial fossa
posterior cranial fossa

Boundaries
Anterior Cranial Fossa Middle Cranial Fossa Posterior Cranial Fossa
Ant inner surface of frontal bone lesser wings of sphenoid sup border of petrous
(with falx cerebri in midline) part of temporal bone
Post sharp lesser wing of sphenoid sup borders of petrous internal surface of
groove for optic chiasma parts of temporal bone squamous part of
occipital bone
Lat squamous parts of
temporal bone
greater wings of sphenoid
parietal bones
Floor lat: orbital plates of frontal greater wing of sphenoid basilar, condylar &
bone squamous and petrous squamous parts of
med: cribiform plate of parts of temporal bone occipital bone
ethmoid mastoid part of temporal
bone

Major Foramina of the Cranial Fossae

Opening in skull Bone of skull Structures transmitted
Ant perforations in ethmoid olfactory n
Cranial cribiform plate
Fossa
Middle 1. optic canal lesser wing of sphenoid optic n
Cranial 2. sup optic fissure b/w lesser & greater lacrimal, frontal, trochlear,
Fossa wings of sphenoid oculomotor, nasociliary &
abducent n;
sup ophthalmic vein

3. foramen rotundum greater wing of sphenoid maxillary division of the

trigeminal n

4. foramen ovale greater wing of sphenoid mandibular division of the

trigeminal n, lesser petrosal n

5. foramen spinosum greater wing of sphenoid middle meningeal art

6. foramen lacerum b/w petrous part of ICA
temporal and sphenoid
Post 1. formen magnum occipital MO, sp part of acc n, R & L
Cranial vertebral art
Fossa 2. hypoglossal canal occipital hypoglossal n

3. jugular foramen b/w petrous part of glossopharyngeal, vagus &

temporal & condylar part acc n; sigmoid sinus  IJV
of occipital
4. int acoustic meatus petrous part of temporal vestibulocochlear & facial n

36
Cavernous Sinus
• It is a large venous space btw the 2 layers of dura mater
• It is situated in the middle cranial fossa, one on either side of the body of the
sphenoid bone

Formation
• floor is by endosteal dura mater
• lat wall, roof & med wall = meningeal dura mater

Extent & Size

• abt 2 cm long & 1 cm wide
• anteriorly: extends up to med end of sup orbital fissure
posteriorly: extends up to apex of petrous temporal

Relations
a) Structures Outside the Sinus
Superiorly 1. optic tract
2. ICA
Inferiorly 1. foramen lacerum
2. jn of body & greater wing of sphenoid bone
Anteriorly sup orbital fissure & apex of orbit
Posteriorly apex of petrous temporal
Medially 1. hypophysis cerebri = pit
2. sphenoidal air sinuses
Laterally temporal lobe of cerebral hemisphere
b) Structures in Lateral Wall of the Sinus
- from above downwards: 1. occulomotor n
2. trochlear n
3. ophthalmic n
4. maxillary n
5. trigeminal ganglion
c) Structures Passing Through the Sinus
1. ICA together with its venous & symp plexuses
2. abducent n

Tributaries
from the orbit 1. sup & inf ophthalmic veins
2. central vein of retina
from the brain 1. supf middle cerebral vein
2. inf cerebral veins
from the meninges 1. sphenoparietal sinus
2. middle meningeal vein (sometimes)

37
Drainage
The cavernous sinus drains into
1. tnvs sinus via sup petrosal sinus
2. IJV via inf petrosal sinus
3. pterygoid plexus of veins via emissary veins
The cavernous sinuses on both sides communicate with each other via
ant & post intercavernous sinuses

Factors which help to expel bld from the sinus are:

a) pulsations of the ICA &
b) gravity

Clinical Notes
1. infection of face may spread via facial vein into cavernous sinus
 thrombosis of cavernous sinus
2. carotid – cavernous sinus aneurysms

38
Superior Sagittal Sinus
It is located in the upper convex margin of the falx cerebri

Course
• begins anteriorly at crista galli by union of meningeal veins
• runs upwards & backwards, becoming progressively larger in size
• ends near int occipital protuberance by deviating to 1 side
usu to the right (continues as R tnvs sinus)

Special Features
• The sinus communicates with 2 or 3 small, irregularly-shaped venous lacunae on
each side
• Arachnoid villi & granulations project into the lacunae

Tributaries
The sinus receives bld from 1. diploic & meningeal veins via the lacunae
2. emissary veins
3. sup cerebral veins

Drainage
It drains into the confluence of sinuses &
hence into the tnvs sinuses & occipital sinus, as well as straight sinus

Surface Anatomy
It extends from above root of the nose, over vault of skull in median plane,
to ext occipital protuberance

Clinical Notes
1. thrombosis caused by spread of infection from nose, scalp & diploe

39
Middle Meningeal Artery
This artery is clinically impt because it is the chief source of extradural hemorrhage

Origin
• branch of maxillary art
• arises in infratemporal fossa deep to ramus of mandible

Course & Relations

• in infratemporal fossa it runs upwards & medially
- deep to lat pterygoid
- passes btw 2 roots of auriculotemporal n
• enters middle cranial fossa through foramen spinosum
• in middle cranial fossa it has an extradural course, running forward & laterally
- related to middle meningeal veins
- divides at a variable pt into ant & post branches

Branches
• The branches arise in the middle cranial fossa
• They contribute to the supply of 1. trigeminal ganglion
2. tympanic cavity
3. orbit
• The terminal branches are
1. ant (frontal) branch - grooves the sphenoid & parietal bones
- supplies ant portion of dura
2. post (parietal) branch - grooves the temporal & parietal bones
- supplies post portion of dura

Surface Marking
Pt 1: at midpt of zygomatic arch = entry of artery into skull
= pt of division of artery
Pt 2: ∼ 2 cm above pt 1
Pt 3: centre of pterion
Pt 4: midpt btw nasion & inion
Pt 5: at lambda sinus
Joining pt 1& 2 - stem of artery
Joining pt 2, 3, & 4 - ant branch
Joining pt 2 & 5 - post branch

Clinical Notes
Injuries to the side of head  fracture of head
This may result in tearing of artery or more commonly via int branch leading to
extradural hemorrhage

40
Types of Intracranial Hemorrhage
Intracranial hemorrhages refer to bleeding inside the cranial cavity
They may result from trauma or vascular lesions
There are 4 main varieties 1. extradural
2. subdural
3. subarachnoid
4. cerebral

Extradural Hemorrhage
• results from injuries to the meningeal arteries or vein
• most common artery to be damaged = ant branch of middle meningeal art
• It is usu torn by a blow to side of the head resulting in fracture of the skull around
the anteroinf region of parietal lobe
• bleeding occurs & a hematoma forms
• the intracranial pressure rises & the bld clot exerts local pressure on underlying
area on precentral gyrus (may result in oppo hemiplegia)
• bld also passes outwards through the fracture line to form a soft swelling under
temporalis muscle

Subdural Hemorrhage
• results from tearing of sup cerebral veins at their pt of entrance into sup sagittal
sinus
• usu caused by blow to the front or back of the head
causing excessive anteropost displacement of the brain within the skull
• once the vein is torn, bld under lower pressure begins to accumulate in the
potential space btw the dura & arachnoid
In ∼ 1/2 the cases, the condition is bilateral
• depending on the speed of accumulation of blood, the clinical condition can be
acute or chronic
• In both cases the bld clod will press against the brim, producing diff pressure
symptoms depending on the location of the clot

Subarachnoid Hemorrhage
• results from leakage or rupture of a congenital aneurysm on the cerebral arterial
cicle (of Willis) or less commonly from an angioma
• the symptoms are sudden in onset & include:
1. severe headache
2. stiff neck
3. loss of consciousness
• It is diagnosed by a lumbar puncture,
where CSF is withdrawn is heavily bld-stained

41
Cerebral Hemorrhage
• generally due to rupture of lenticulostriate artery,
which is a branch of middle cerebral art
• inv corticolubar & corticospinal fibres in internal capsule
• produces hemiplegia on oppo iside of body
• the patient immediately loses consciousness & paralysis is evident when
consciousness is regained

42
Internal Carotid Artery (Petrous, Cavernous & Cervical
Parts)
The cervical part of the ICA enters the carotid canal in the petrous part of the
temporal bone, to continue as the petrous part

Petrous • runs in the carotid canal

Part • closely related to cochlea, middle ear & auditory tube, as well as
trigeminal ganglion
• at the foramen lacerum it asc to a pt med to lingual of sphenoid bone
• enters cavernous sinus to continue as the cavernous part
• gives branches to tympanic cavity
Cavernous • runs forward in the sinus along side of sella turcica
Part • sep from bld in the sinus by endothelial lining of the sinus
• asc & pierces dural roof of sinus btw ant & post clinoid processes to
continue as cerebral part
• gives branches to the meninges as well as inf hypophyseal branch
Cerebral • turns backward in subarachnoid space below optic n
Part • asc & at med end of lat sulcus divides into ant & middle cerebral art

Branches of Cerebral Part

1. sup hypophpyseal art
2. ophthalmic art
3. post commnunicating art
4. ant choroid art (choroid plexus of lat ventricle)
5. ant cerebral art – terminal branch
6. middle cerebral art – terminal branch

Clinical Notes
1. If collateral circulation is good, the ICA on 1 side can be ligated or occluded
without any effect
2. In ant & middle cerebral arteries are occluded
 various neural defects because they supply parts of the brain

43
Trigeminal Ganglion
• This is the sensory ganglion of the 5th cranial n (trigeminal n)
• It is made up of pseudounipolar n cells, each with
• a peripheral & a central process

Location
• lies on the trigeminal impression on ant surface of petrous temporal near its apex
• occupies a special space in the dura mater called trigeminal (or Merkel) cave

Shape
• cresenteric / semilunar in shape
• convexity is directly anterolaterally,
where the 3 divisions of the trigeminal n emerge
• concavity is post & receives sensory root of the nerve

Relations
Superiorly parahippocampal gyrus
Inferiorly 1. motor root of 5th n
2. greater petrosal n
3. apex of petrous temporal
4. foramen lacerum
Medially 1. ICA
2. post part of cavernous sinus
Laterally middle meningeal artery

Roof
• formed by central processes of ganglion cells
 sensory root to trigeminal n
• attached to pons at its jn with middle cerebellar peduncle

Branches
= 3 divisions of the trigeminal n
1. ophthalmic n
2. maxillary n
3. mandibular n
These are formed by the peripheral processes of the ganglion cells

Blood Supply
twigs from 1. ICA
2. middle meningeal
3. accessory meningeal &
4. meningeal branches of asc pharyngeal arteries

Clinical Notes
1. ganglion can be blocked by passing a needle through the mandibular notch &
foramen ovale & injecting an anesthetic

44
2. the sensory root may be surgically sectioned in the middle cranial fossa to relieve
facial pain due to trigeminal neurolgia or carcinomatosis

45
Structure of the Eyeball
The eyeball consists of 3 coats:
1. ext, protective fibrous coat
2. middle, vascular pigmented coat &
3. int nervous coat
It contains the aqueous humour, lens & vitreous body

Coats of the Eyeball

a) External Fibrous Coat
This is made up of an ant transparent part: the cornea
& a post opaque part, the sclera
Cornea • largely responsible for refraction of light
• its transparency depends on its hydration
• avascular  nourished by permeation
• supplied by ophthalmic n via ciliary branches
Sclera • composed of dense fibrous tissue & is white in colour
• pierced by ciliary arteries & nerves
• posteriorly, pierced by optic n (at lamina cribosa)
• receives tendons of muscles of the eyeball

b) Middle Vascular Coat

This comprises, from bhd forwards, the choroid, ciliary body & iris
Choroid • brown coat lining the greater part of the sclera
• consists of outerpigmented layer & inner vascular layer
Ciliary • connects the choroids to the iris
Body • composed of 1. ciliary ring
2. ciliary muscles
3. ciliary processes
Note: ciliary muscles - supplied by psymp fibres from ciliary ganglion
- their contraction results in the lens becoming
more convex
 high refractive power of the lens
Iris • circular pigmented diaphragm, its aperture know as the pupil
• lies in front of the lens
• divides space btw cornea & lens into ant & post chambers,
both of which are filled with aqueous humour
• contain muscles fibres forming
1. sphincter papillae (supplied by psymp fibres from occulomotor
n)
2. dilator papillae (supplied by symp fibres from LC plexus)

46
c) Internal Nervous Coat
This is called the retina
- consists of: outer pigmented layer
inner nervous layer
- ant portion is non-receptive & is sep from post part by the ora serrata
- post part has the following features
1. macula lutea (yellow spot)
2. fovea centralis = central pit in the macula lutea
3. optic disc, where the optic n leaves the retina
This is called the blind spot because of lack of receptors
The optic disc is pierced by the central artery of the retina

Contents of the Eyeball

This consists of the aqueous humour, lens & vitreous body
Aqueous • fills ant & post chambers of eye
Humour • composition is approx that of protein-free plasma
• formed by ciliary processes
• functions 1. support wall of eyeball by exerting pressure
2. nourishes lens & remove products of metabolism
Lens • transparent & biconvex
• situated bhd iris & in front of vitreous body
• consist of 1. elastic capsule
2. cuboidal epithelium
3. lens fibres
• capsule is attached to ciliary body by suspensory lig of the lens
 contraction of ciliary muscles of ciliary body will alter the
shape of the lens
Vitreous Body • transparent gelatinous mass enclosed by vitreous mbm
• fills the eyeball bhd the lens
• functions 1. supports post surface of lens
2. contribute to magnifying power of eye

Sensory Nerve Supply

short & long ciliary n from nasociliary n

Blood Supply
Ophthalmic art

Venous Drainage
into cavernous sinus

47
Movements of the Eyeball
• The movements of the eyeball are commonly resolved into those taking place
around 3 primary axes: 1. vertical axis
2. tnvs axis
3. anteropost axis
• The position of rest is that in which the gaze is straight ahead  1° position
• Equilibrium is maintained by all the eyeball muscles,
which practically do not act alone but as a gp
• Movements of the eyes are brought abt by
an increase in tone in 1 set of muscles &
a decrease in tone of the antagonistic muscles

Movement around Vertical Axis

The reference pt is the centre of the cornea,
& the movements are abduction & adduction,
both rotatory movements of the eyeball
Abduction • centre of cornea moves laterally
• muscles acting: 1. lat rectus
2. sup oblique
3. inf oblique
Adduction • centre of cornea moves medially
• muscles acting: 1. med rectus
2. sup rectus
3. inf rectus

Movement around Transverse Axis

The reference pt is again the centre of the cornea,
& the movements are elevation & depression,
both also rotatory movements
Elevation • centre of cornea moves upward
• muscle acting 1. sup rectus
2. inf oblique
Depression • centre of cornea moves downward
• muscles acting 1. inf rectus
2. sup oblique

Movement around Anteroposterior Axis

The reference pt is now the top part of the cornea
& the movements are intorsion & extorsion
both also rotatory movements
Extorsion • top part of cornea moves laterally
• muscles inv 1. inf rectus
2. inf oblique
Intorsion • top part of cornea moves medially
• muscles inv 1. sup rectus
2. sup oblique

48
Clinical Notes
Paralysis of a muscle of the eyeball is noted by
1. limitation of eye movement in the field of action of paralysed muscle
2. production of 2 images (diplopia) which are separated maximally when an attempt
is made to use the paralysed muscle

Innervation
Occulumotor n • supplies all extraocular muscles except LR & SO
• damage results in
1. ptosis (paralysis of levator palpebrae sup)
2. abduction (unoppo action of LR & SO)
3. limitation of movement
4. double vision = diplopia
5. dilatation of pupil (paralysis of sphincter)
6. inability to accommodate (paralysis of ciliary muscles)
Trochlear n • supplies sup oblique
• Damage results in limitation of movement & diplopia
when the subject is asked to look downwards with eye adducted
Abducent n • supplies lat rectus
• Damage results in inability to abduct the eye
beyond the middle of the palpebral fissure

49
Ophthalmic Artery
This is the main bld supply of the orbit

Origin
• branch of cerebral part of ICA
• given off med to ant clinoid process

Course & Relations

• enters orbit through orbital canal
- inferolat to optic n
• runs forward at first lat to optic
then crosses the nerve from above tog with nasociliary n
• runs along med wall of orbit
• terminates near med angle of eye
- by dividing into supratrochlear & dorsal nasal branches

Branches
Branches Supply
central artery of the retina retina
post ciliary arteries ciliary body & iris
muscular branches iris & ciliary body
(gives rise to ant ciliary arteries)
lacrimal artery lacrimal gld
supra-orbital artery upper eyelid & scalp
supratrochlear artery forehead & scalp
dorsal nasal artery root & lacrimal sac

Clinical Notes
Occlusion of ophthalmic artery / central artery of retina leads to blindness

50
Lacrimal Apparatus
• The structures concerned with secretion & drainage of tears constitute the lacrimal
apparatus
• It is made up of 1. lacrimal gld & its ducts
2. lacrimal canaliculi
3. lacrimal sac
4. nasolacrimal duct
Lacrimal Gland
• located in fossa on anterolat angle of roof of orbit
• rests on lat rectus & levator palpebrae sup
• consists of 2 parts: orbital part
palpebral part
which are continuous with each other around the lat border of aponeurosis of the
levator palpbrae sup
• it is drained by ∼12 lacrimal ducts which open into the sup fornix of the
conjunctiva
• Nerve Supply
Psymp • PreGN fibres derived from lacrimal nucleus of facial nerve
Supply - travel in petrosal n
- synapse in pterygopalatine ganglion
• PGN fibres join maxillary n
- then pass into zygomatic branch & zygomaticotemporal n
- reach the lacrimal gld within lacrimal n
Symp • fibres from sup cervical ganglion
Supply • reach the gld by way of lacrimal n

Lacrimal Canaliculi
• 1 in each eyelid, ∼1 cm long
• begins as lacrimal punctum
• pass medially
• open into lat wall of lacrimal sac

Lacrimal Sac
• located in a fossa at med margin of orbit, btw ant & post lacrimal crests
• ∼ 1 to 1 1/2 cm in length
• related to anteriorly to med palpebral lig
posteriorly to lacrimal part of orbicularis oculi
laterally to ethmoidal air cells & middle meatus

Nasolacrimal Duct
• ∼ 2 cm long
• extends from lower end of lacrimal sac to inf meatus of nose
• situated in a bony canal
• its opening is guarded by a fold of mucous mbm = lacrimal fold

Clinical Notes
Inflammation of lacrimal sac  overflow of tears & discharge of pus

51
Vertebral Artery
• This is 1 of the 2 principal arteries supplying the brain
• In addition, it also supplies the spinal cord, meninges, & the surrounding muscles
& bones

Origin
branch of 1st part of subclavian art

Course & Relations

The course is complicated & can be considered in 4 parts
Cervical (1st) • extends from origin to tnvs process of CV7
Part • enters foramen in tnvs process of CV6
• ant relations 1. carotid sheath & CCA
2. vertebral vein
3. inf thyroid artery
4. on L side: thoracic duct
• post relations 1. tnvs process of CV7
2. stellate ganglion
3. ventral rami of CV7, 8
nd
Vertebral (2 ) extends from tnvs processes of CV6 to CV1
Part ie. runs through the foramina of the upper 6 CV
emerge from tnvs process of atlas
Suboccipital (3rd) • winds medially bhd lat mass of atlas
Part • enters vertebral canal after piercing dura mater & arachnoid
mater
• passes through foramen magnum  then makes a sharp loop
Intracranial (4th) • asc medially in front of medulla oblongata
Part • at lower border of pons, the vertebral arteries
unite to form the basilar artery

Branches
Cervical Branches 1. spinal
2. muscular
Cranial Branches 1. meningeal branches
2. post spinal artery
3. medullary arteries

Clinical Notes
1. thrombosis of vertebral artery (occlusion)
2. lesion of ant spinal artery
3. lesion of post inf cerebellar artery

52
Suboccipital Triangle
• deep to semispinalis capitis & splenius capitis
• Boundaries
med rectus capitis post major
superolat oblique capitis sup
inferolat oblique capitis inf
• contents: 1. vertebral venous plexus
2. 3rd part of vertebral art (in groove of post arch of atlas)
3. suboccipital n (beneath vertebral art)
• Greater occipital n - lies on roof of triangle
before piercing semispinalis capitis
to be distributed to skin of occipital region

53
Parotid Gland
This is the largest of the salivary glds. It is almost entirely serous in nature

Location
• situated below ext auditory meatus
• lies in deep hollow bhd ramus of madible & in front of the sternocleidomastoid

Shape & Parts of the Gland

Shape: roughly wedge-shaped,
with the base above & the apex bhd angle of the mandible
Parts: facial n divides the gld into: 1. supf lobe
2. deep lobe

Processes
1. glenoid process
2. facial process
3. pterygoid process

Capsules
• 2 capsules: inner fibrous capsule
outer capsule derived from investing layer of deep cervical fascia
• A portion of fascia btw styloid process & mandible is thickened to form the
stylomandibular lig

Relations
• For purposes of description, the relations are divided into supf, sup, posteromed &
anteromed
Superficial 1. parotid lymph nodes
2. great auricular n
3. supf fascia & skin
Superior 1. ext auditory meatus
2. post surface of temporomandibular jt
Glenoid process is directly related to auriculotemporal n
Posteromed 1. mastoid process
2. sternocleidomastoid
3. post belly of digastric
4. styloid process & its attached muscles - stylohyoid
stylopharyngeus
styloglossus
5. carotid sheath with ICA, IJV & vagus
6. IX, XI & XII cranial n
7. facial n
Anteromed 1. post border of ramus of mandible
2. temporomandibular jt
3. masseter
4. med pterygoid
5. terminal branches of facial n
6. stylomandibular lig

54
• At the union of anteromed & posteromed surfaces the gld lies in contact with
pharyngeal wall
• The ant border of the gld is formed by union of supf & anteromed surfaces
From the border several structures emerge
1. parotid duct
2. terminal branches of facial n
3. tnvs facial vsls

Structures Within the Gland

From lat to med, these are:
1. facial n & terminal branches
2. retromandibular vein - ant division  facial vein  IJV
post division  joins post auricular vein  EJV
3. ECA  supf temporal art
 maxillary art
4. some members of parotid gp of lymph vsls

Parotid Duct
• emerges from facial process of the gld
• passes forward over lat surface of masseter
• at ant border of masseter, it turns medially
to pierce buccal pad of fat & buccinator
• runs forward briefly btw buccinator & oral mucous mbm
• opens into vestibule of mouth opposite upper 2nd molar tooth
Note: its oblique course acts as a valve to prevent infection of the duct during
chewing

Blood Supply
ECA & its terminal branches  supf temporal art
 maxillary art

Venous Drainage
into retromandibular vein  facial & EJV

Lymphatic Drainage
into parotid lymph nodes  deep cervical nodes

55
Nerve Supply
a) Psymp = secretomotor
PreGN fibres • arise from inf salivatory nucleus
• travel via 9th cranial n
• synapse in otic ganglion
PGN fibres • pass through auriculotemporal n
• reach the gld

b) Symp = vasomotor
- derived from plexus around ECA
c) Sensory
- from auriculotemporal n
- also, parotid fascia is supplied by sensory fibres from great auricular n

Clinical Notes
1. parotid fascia is unyielding  parotid swellings are painful
2. viral infection  mumps
3. inflammation of retrograd bacterial infection from parotid duct
4. tumour of parotid gld
- if malignant, usu inv the facial n  unilat facial paralysis
5. penetrating wounds of parotid that damage auriculotemporal & great auricular n
 Frey’s syndrome
ie sweating over parotid region when patient eats

56
Temporomandibular Joint

Type
It is a synovial jt

Articulation
• btw 1. articular tubercle & ant part of mandibular fossa
of temporal bone above
2. head of mandible below
• articular surfaces covered with fibrocartilage

Capsule
• surrounds the jt
• attachments: above – to articular tubercle & margin of mandibular fossa
below – to neck of mandible

Ligaments
lat temporomandibular lig lat
sphenomandibular lig med
stylomandibular lig posteromed
articular disc divides the jt into upper & lower compartments

Synovial Membrane
lines the capsule in both compartments

Blood Supply
1. supf temporal artery
2. maxillary artery
(Both from ECA)

Nerve Supply
branches of mandibular n: 1. auriculotemporal
2. masseteric
3. deep temporal

Relations
Anteriorly 1. mandibular notch
2. masseteric n & artery
Posteriorly 1. tympanic plate of ext auditory meatus
2. glenoid process of parotid gld
Medially 1. maxillary art & vein
2. auriculotemporal n
Laterally 1. parotid gld
2. fascia & skin

57
Movements
In the position of rest, the upper & lower teeth are separated by a slight interval
The movements are
Movements Muscles involved
1 depression of mandible 1. lat pterygoids
(opening of mouth) 2. digastrics
3. geniohyoids & mylohyoids
2 elevation of mandible 1. masseter
(closure of mouth) 2. temporalis
3. med pterygoids
3 Protusion of mandible 1. lat pterygoids
2. med pterygoids
4 Retraction of mandible 1. post fibres of temporalis
5 Lateral movements med & lat pterygoids of each side acting
(side-to-side chewing movements) alternatively

Clinical Notes
1. Dislocation of mandible
2. detachment of articular disc  clicking sounds when the jaw is moved

58
Movements of the Mandible
• The movements of the mandible are controlled more by the play of muscles than
by either the shape of the articular surfaces or the ligaments
• In the position of rest, the teeth of the upper & lower jaws slightly apart. On
closure of the jaws the teeth come into contact
• The chief movements are 1. depression
2. elevation
3. protrusion
4. retraction
5. lateral movement

Movements
Movements Results in Mechanism Muscles inv
of the
Mandible
Depression opening of • head of mandible rotates around horiz 1. lat pterygoids
the mouth axis under the articular disc 2. digastrics
• both head & disc are then pulled 3. geniohyoids &
forwards so that the disc now moves mylohyoids
onto articular tubercle
• head now articulates with most ant
part of disc
Elevation Closing of • head of mandible & articular disc 1. masseter
the mouth moves backwards 2. temporalis
• head then rotates under the articular 3. med
disc pterygoids
 opposite movement from
depression
Protrusion Lower • articular disc pulled forward onto ant 1. lat pterygoids
teeth drawn tubercle tog with head of mandible 2. med
forwards • Thus a movement occurs in upper pterygoids
beyond compartment of jt
upper teeth
Retraction Mandible articular disc & head of mandible are 1. post fibres of
drawn pulled backward into mandibular fossa temporalis
backwards 2. may be
to postion assisted by
of rest masseter
Lateral • by alternately protruding & retracting 1. med pterygoid
Chewing the mandible on each side 2. lat pterygoid
• For this to take place, a certain amt of
rotation occurs & the muscles
responsible on both sides work
alternatively & not in unison

Clinical Notes
Dislocation of the mandible sometimes occurs when the mandible is depressed
The head of the mandible on 1 or both sides slips anteriorly into infratemporal fossa
 inability to close mouth

59
Maxillary Artery
The maxillary artery has an extensive distribution to the upper & lower jaws, muscles
of mastication, the palate & the nose

Origin
• It is the larger terminal branch of ECA
• arises in parotid gld bhd neck of mandible

Course & Relations

For descriptive purposes the artery is divided into 3 parts by the lat pterygoid
Mandibular (1st) Part • from its origin it runs forward
• lies btw neck of mandible & sphenomandibular lig
• reaches & runs along lower border of lat pterygoid
• from lower border of pterygoid,
nd
Pterygoid (2 ) Part
it runs upwards & forwards
either supf or deep to lower head of lat pterygoid
• passes btw the 2 heads of lat pterygoid
rd
Pterygopalatine (3 ) Part
• then through pterygomaxillary fissure
to enter the pterygopalatine fossa
• breaks up into branches, of which the
sphenopalatine art is considered the terminal branch

Branches
From 1st Part gives off 5 branches of which the most impt is
middle meningeal art & inf alveolar art
From 2nd Part branches supply the muscles of mastication as well as the buccinator
From 3rd Part the more impt are:
1. infraorbital art
2. greater palatine
3. pharyngeal
4. spenopalatine

Clinical Notes
1. middle meningeal artery inv in intracranial hemorrhages
2. sphenopalatine artery inv in nosebleeds

60
Maxillary Nerve
The maxillary nerve is the 2nd division of the trigeminal n

Origin
• arises from trigeminal ganglion
• lies in dura lat to cavernous sinus

Course & Relations

• from origin, it passes through foramen rotundum
• enters pterygopalatine fossa
• continues as infraorbital n
• enters orbit through inf orbital fissure
• runs in infraorbital groove then canal
• passes through infraorbital foramen
• emerges onto the face where it ends by dividing into several branches

Branches
1 meningeal branch in middle cranial fossa
2 post sup alveolar branches in pterygopalatine fossa
3 zygomatic n
4 middle & ant sup alveolar branch in infraorbital canal
5 inf palpebral branches on face
6 nasal branches
7 sup labial branches

Clinical Notes
In the pterygopalatine fossa, the nerve can be blocked by passing a needle through the
mandibular notch & injecting a local anesthetic

61
Mandibular Nerve
• The mandibular n is the 3rd & largest of the 3 division of the trigeminal n
• It has both sensory & motor fibres

Origin
• begins in the middle cranial fossa as a large sensory root & a small motor root
• sensory root arises from trigeminal ganglion
• motor root arises from motor nucleus of V in pons

Course & Relations

• sensory root lies above motor root & both pass out of the skull through foramen
ovale to enter infratemporal fossa
• the 2 roots unite just below the foramen to form a single main trunk
- lies on tensor palatini, deep to lat pterygoid
• the main trunk soon divides into a small ant & large post division

Branches
1. From Main Trunk
1. meningeal branch
2. n to med pterygoid
From Sensory Motor
2. Anterior Trunk / Division buccal n 1. masseteric n
2. deep temporal n
3. n to lat pterygoid
3. Posterior Trunk / Division 1. auriculotemporal n inf alveolar n
2. lingual n

Clinical Notes
1. mandibular n block carried out intra-orally for extraction of teeth
2. pain from disease of the tooth sometimes gets referred along the auriculotemporal
n to the ear

62
Pterygopalatine Ganglion
• This is a larger psymp peripheral ganglion
• It serves as a relay station for the secretomotor fibres to the
lacrimal gld & mucous glds of the nose, paranasal sinuses, palate & pharynx

Location
• lies in pterygopalatine fossa - below maxillary n in front of pterygoid canal
close to sphenopalatine foramen

Connections (Roots)
a) Motor (psymp) root = secretomotor
formed by 1. greater petrosal n
2. n of pterygoid canal
PreGN fibres • arise from lacrimal nucleus
• pass through nervous intermedius of facial n
• synapse in the ganglion
PGN fibres • pass to lacrimal gld via maxillary, zygomatic & lacrimal n
• also pass to nasal & palatine glds

b) Symp root = vasomotor

- formed by 1. deep petrosal n
2. n of pterygoid canal
- fibres derived from ICA plexus & they are PGN fibres having come from sup
cervical ganglion
- these fibres pass through ganglion without synapsing
- they are distributed with the psymp fibres
c) Sensory root
- from maxillary n
- pass through the ganglion without synapsing

Branches
These are branches of the maxillary n which also incorporate psymp & symp fibres
1. orbital branches
2. palatine branches (greater & lesser)
3. nasal branches
4. pharyngeal branches

Clinical Notes
The ganglion can be injected through the mandibular notch & pterygopalatine fossa

63
Submandibular Gland
The submandibular gld is a large salivary gld and has a mixture of serous and mucous
acini.

Location
• it lies in the ant part of digastric triangle
• partly under cover of body of mandible

Shape & Parts of the Gland

• roughly J-shaped
• divided into 1. large supf part (supf to mylohyoid)
2. small deep part (deep to mylohyoid)
The 2 parts are continuous with each other around post border of mylohyoid

Capsules
• 2 capsules cover the gld:
1. int fibrous capsule
2. ext capsule derived from investing layer of deep cervical fascia
• Part of fascia extends btw styloid process & angle of mandible
 stylomandibular lig

Superficial Part of Gland

• lies in digastric triangle, partly under cover of mandible
• posteriorly it is separated from parotid gld by stylomandibular lig
• Relations
anteriorly ant belly of digastric
posteriorly 1. stylohyoid
2. post belly of digastric
3. stylomandibular lig, which sep it from
4. parotid gld
medially 1. mylohyoid
2. mylohyoid n & vsls
3. hyoglossus
4. lingual & hypoglossal n
laterally 1. submandibular fossa on med surface of mandible
2. cervical branch of facial n
3. facial vein
4. submandibular lymph nodes
5. fascia, platysma & skin inferolaterally

64
Deep Part of the Gland
• extends forward to interval btw: mylohyoid (below & lat)
& hyoglossus & styloglossus (med)
• post end is continuous with supf part of gld around post border of mylohyoid
muscle
• ant end reaches as far as sublingual gld
• Relations
anteriorly sublingual gld
posteriorly 1. stylohyoid
2. post belly of digastric
3. stylomandibular lig
4. parotid gld
superiorly 1. lingual n
2. submandibular ganglion
3. It is covered by mucous mbm of floor of the mouth
inferiorly hypoglossal n
medially hyoglossus & styloglossus
laterally 1. mylohyoid
2. supf part of the gld

Submandibular Duct
• emerges from ant end of deep part of gld
• passes forward along side of the tongue, beneath mucous mbm of floor of mouth
• opens into the mouth on the summit of a small papilla situated at the sides of the
frenulum of the tongue

Blood Supply
branches of 1. facial art &
2. lingual art

Venous Drainage
1. facial vein
2. lingual vein

Lymphatic Drainage
submandibular nodes  deep cervical nodes

Nerve Supply
Psymp • secretomotor
• fibres from sup salivatory nucleus of 7th cranial n  PreGN
• pass via chorda tympani  lingual n  synapse in submandibular ganglion
• PGN fibres reach gld directly from the ganglion
Symp from plexus on facial art
Sensory from lingual n

Clinical Notes
1. common site for formation of calculus (stones)
2. excision of gld

65
Sublingual Gland
• This is the smallest of the 3 main salivary glands
• It contains both serous & mucous acini, with mucous predominating

Location & Shape

• lies beneath mucous mbm of floor of mouth
close to midlin
• roughly almond-shaped

Relations
Anteriorly gld on opposite side
Posteriorly deep part of submandibular gld
Medially 1. genioglossus
2. lingual n
3. submandibular duct
Laterally sublingual fossa on med surface of mandible
Superiorly mucous mbm of floor of the mouth
 elevated to form sublingual fold
Inferiorly mylohyoid muscle

Sublingual Ducts
• 8-20 in number
• majority open into mouth on summit of sublingual fold
• some may open into submandibular duct

Blood Supply
branches of 1. facial art
2. lingual art

Venous Drainage
1. facial vein
2. lingual vein

Lymphatic Drainage
submandibular  deep cervical nodes

Nerve Supply
Psymp • PreGN fibres from sup salivary nucleus of 7th cranial n
 chorda tympani  lingual n  submandibular ganglion
• PGN fibres  lingual n  supply the gld
Symp from plexus around facial & lingual arteries
Sensory from lingual n

Clinical Notes
1. infection & enlargement of gld
2. blockage of one of the sublingual ducts  cysts

66
Lingual Nerve
• The lingual n is sensory to the ant 2/3 of the tongue & fibre of the mouth
• In addition it also receives fibres from the chorda tympani branch of the facial n
1. secretomotor (psymp) to submandibular & sublingual salivary glds
2. taste fibres to ant 2/3 of tongue

Origin
• 1 of the 2 terminal branches of post dividision of mandibular n
• begins slightly below skull (stylomandibular lig)

Course & Relations

• runs downward on med surface of lat pterygoid
• then on lat surface of med pterygoid
• joined by chorda tympani
• emerges at lower border of lat pterygoid & continues downwards btw ramus of
mandible & med pterygoid
• next it passes forward & medially beneath lower border of sup constrictor of
pharynx
- medially it is related to styloglossus
laterally it is related to lower 3rd molar tooth
• passes forward on lat surface of hyoglossus
• at ant margin of hyoglossus, it winds round submandibular duct from lat to med &
lies on genioglossus
• divides into terminal branches

Branches
ganglionic • PreGN psymp fibres passing to submandibular ganglion
branches • These fibres arise from sup salivatory nucleus of facial n
 travel via chorda tympani  lingual n
sensory branches to ant 2/3 of the tongue, floor of mouth & lingual surface of gums
communicating to hypoglossal n
branches

Clinical Notes
Close relation of lingual n to 3rd molar tooth
 may be damaged during tooth extraction

67
Nasal Cavity: Relations, Openings & Branches
• The nasal cavity extends from the nostrils (nares) in front to the choanae bhd
• It is divided into 2 halves by the nasal septum

Relations
Superiorly 1. frontal sinus
2. ant cranial fossa
3. sphenoidal sinus
4. middle cranial fossa
Inferiorly 1. hard palate, which sep it from
2. oral cavity
Posteriorly communicates with nasopharynx which
can be regarded as the back of the cavity
Laterally 1. exterior (front part of cavity)
2. orbit
3. maxillary & ethmoid sinuses
4. pterygopalatine & pterygoid fossae

Openings
The openings that lead into or out of the nasal cavity are:
1. nostrils
2. choanae
3. openings of maxillary, frontal, sphenoidal & ethmoidal air sinuses, &
4. opening of nasolacrimal duct

Nostrils • ant aperturesof the nose

• perforate ext nose to communicate with exterior
• bounded medially by nasal septum
laterally by ala of the nose
Choanae • post aperture of the nose, larger than the nostrils
• communicate with nasopharynx
• bounded superiorly by body of sphenoid
inferiorly by horiz plate of palatine bone
medially by vomer &
laterally by med pterygoid plate
Openings of Paranasal Air
Sinuses
1. maxillary sinus • opens into middle meatus of nasal cavity through
hiatus semilunaris
2. frontal sinus • opens into middle meatus via infundibulum
3. sphenoidal sinus • opens into sphenoethmoidal recess
4. ethmoidal sinuses • ant & middle gps open into middle meatus
post gp opens into sup meatus
Opening of Nasolacrimal • opens into inf meatus of nasal cavity
Duct • opening is guarded by a fold of mucous mbm
= lacrimal fold

68
Boundaries
each half of the nasal cavity has a roof, floor, med & lat walls
Formation Remark
Roof 1. nasal cartilages the roof is narrow & slopes
2. nasal bone downwards
3. frontal bone
4. cribiform plate of ethmoid bone
5. body of sphenoid
( from ant to post)
Floor 1. palatine process of maxilla (ant) separates nasal cavity from oral
2. horiz plate of palatine bone (post) cavity
 upper surface of hard palate
Medial 1. septal cartilage • consists of nasal septum
Wall 2. perpendicular plate of ethmoid • usu deviated to one side
3. vomer ( from ant to post)
Lateral 1. nasal bone
Wall 2. maxilla bone
3. lacrimal bone
4. ethmoid (labryrinth & concave)
5. inf nasal concha
6. perpendicular plate of palatine
7. med pterygoid plate sphenoid

Blood Supply
maxillary art  sphenopalatine art
ophthalmic art  ant ethmoidal art

Venous Drainage
Veins follow the arteries

Lymphatic Drainage
deep cervical nodes

Nerve Supply
1. Psymp from pterygopalatine ganglion
2. Symp from sup cervical ganglion

69
Features
1. 3 projections
sup choncha part of ethmoid bone
middle choncha part of ethmoid bone
inf choncha sep bone by itself
2. area below each choncha is called meatus
sup meatus • lies below & lat to sup choncha
• receives opening of post gp of ethmoidal sinuses
middle • lies below & lat to middle choncha
meatus • ethmoidal bulla = opening of middle ethmoidal sinuses
• hiatus semilunaris = opening of maxillary sinus
• ethmoidal infundibulum = opening of frontal sinus &
ant ethmoidal sinuses
inf meatus • lies below & lat to inf choncha
• receives openings of nasolacrimal duct, guarded by an
imperfect valve, the lacrimal fold

Clinical Notes
1. fracture of nasal bones & nasal septum due to frontal blows
2. spread of infection from nasal cavity into intracranial regions
3. epistaxis / nose bleed
- inv sphenopalatine & facial vsls

70
Tongue: Features & Muscles
• The tongue is a muscular organ in the floor of the mouth
• It is attached by muscles to the hyoid bone, mandible, stylod processes & pharynx
• It is impt in taste, mastication, swallowing & speech

Surface Features
• The tongue is composed chiefly of skeletal muscle & covered by mucous mbm
• Its ant 2/3 lies in the mouth & post 2/3 in the pharynx
• It presents 1. tip & margin
2. dorsum
3. inf surface
4. root
a) Tip & Margin
- The tip / apex of the tongue usu rests against the incisor teeth
- The margin of the tongue is related on each side to the gums & the teeth
b) Dorsum
- situated partly in oral cavity & partly in oropharynx
- This is demarcated by a V-shaped groove = sulcus terminalis
which divides it into ant 2/3 in oral cavity
post 1/3 in oropharynx
- apex of sulcus terminalis projects backwards
& is marked by a small pit = foramen cecum
Oral Part of Tongue 1. divided into L & R halves by shallow
median groove
2. exhibit lingual papillae of the 3 types
a. filiform papillae
b. fungiform papillae
c. vallate papillae
Pharyngeal Part of Tongue contains lymphatic nodules = lingual tonsils
= ant wall of pharynx devoid
of papillae
c) Inferior Surface
- smooth & devoid of papillae
- connected to floor of mouth by a fold of mucous mbm = frenulum of tongue
- deep lingual vein can be seen beside frenulum
- lat to vein mucous mbm forms a fold = plica fimbriatia
d) Root
- rests on floor of mouth, ie. geniohyoid & mylohyoid
- attached by muscles to mandible & hyoid bone
- nerves, vsls & extrinsic muscles enter or leave the tongue through its root

71
Muscles of the Tongue
• These muscles of the tongue are of 2 types 1. intrinsic
2. extrinsic
• All the muscles are bilateral, those on 1 side being partially separated from those
of the opposite side by a median septum
Intrinsic • These muscles are confined to the tongue itself & are not
Muscles attached to bone
• They are arranged in several planes & are generally classified
as
1. sup & inf longitudinal
2. tnvs
3. vertical
• Their actions are to alter the shape of the tongue
Extrinsic • These muscles that arise from nearby parts & are inserted into
Muscles the tongue
• They are: 1. genioglossus
2. hyoglossus
3. styloglossus
4. palatoglossus
• Their actions are to move the tongue

Movements of the Tongue

1 protrusion brought abt by genioglossus of both sides acting tog
2 retraction produced by styloglossus & hyoglossus of both sides acting tog
3 depression produced by hyoglossus & genioglossus of both sides acting tog
The shape of the tongue is modified by the action of the intrinsic muscles

Blood Supply
1. lingual art
2. tonsillar branch of facial art
3. asc pharyngeal art

Lymphatic Drainage
tip submental nodes
ant 2/3 submandibular  deep cervical nodes
post 1/3 deep cervical nodes

72
Innervation of the Tongue
The nerve supply of the tongue is 2 fold:
1. motor supply to the muscles
2. sensory to the mucous mbm

Motor Supply
• All intrinsic muscles are supplied by hypoglossal n
• All extrinsic muscles are also supplied by hypoglossal n
except palatoglossus which is supplied by cranial part of accessory n
• Thus the nerves concerned with motor supply to the tongue are the 11th & 12th
cranial n

Sensory
Ant 2/3 of Tongue 1. supplied by lingual n (a branch of mandibular n)
for general sensation
2. supplied by chorda tympani (a branch of facial n)
for taste
Note: chorda tympani runs in lingual n
Post 1/3 of Tongue 1. supplied by lingual branch of glossopharyngeal n
for both general sensation & taste
2. small contribution from int laryngeal branch of vagus n
for both general sensation & taste
Thus the nerves concerned with sensory supply come from:
1. 5th cranial n = general sensation
th
2. 7 cranial n = taste
3. 9th cranial n = both
4. 10th cranial n = both

Clinical Notes
1. lesion of hypoglossal n  paralysis of ipsilat side of tongue
2. lesion of facial n  loss of taste sensation on ant 2/3 of tongue

73
Constrictor Muscles of Pharynx
• The wall of the pharynx is composed largely of 2 layers of muscles
• The internal, chiefly longitudinal layer consists of 2 levator muscles:
1. palatopharyngeus
2. stylopharyngeus
• The outer circular layer consists of 3 constrictors
1. sup constrictors
2. middle constrictors
3. inf constrictors
The constrictors have their fixed pts in front,
where they are attached to bones & cartilage,
whereas they expand bhd & overlap one another from below upwards.
They end in a median tendinous raphe posteriorly

The Constrictor Muscles

Superior Constrictor Middle Constrictor Inferior Constrictor
Origin 1. post border of med 1. lower part of 1. oblique line on lamina on
pterygoid plate stylohyoid lig thyroid cartilage
2. pterygoid hamulus 2. lesser & greater 2. tendinous band connecting
3. post end of mylohyoid line cornus of hyoid thyroid cartilage to cricoid
on mandible bone cartilage
4. side of tongue 3. side of cricoid cartilage
Insertion 1. upper fibre curve med & • into median • Into median tendinous
upwards tendinous raphe raphe
 pharyngeal tubercle of
• Sup fibres • Sup fibres overlap lat
occipital bone
overlap lat surface of middle
2. middle fibres  median
surface of sup constrictor muscle
tendinous raphe
3. lower fibres curve med &
constrictor • Inf fibres run horizontally
downward  median • inf fibres are med & are continuous with
tendinous raphe overlapped circular fibres of
They are overlapped by laterally by inf esophagus below
middle constrictors constrictor
Nerve pharyngeal plexus pharyngeal plexus pharyngeal plexus
Supply

Action of Constrictor Muscles

During process of swallowing,
1. upper fibres of sup constrictor contract & pull the post pharyngeal wall forward
 aids palate in closing off upper part of pharynx (nasopharygnx)
2. successive contraction of the sup, middle & inf constrictor muscles propels the
bolus of food down into the esophagus
3. the lowest fibres of inf constrictor (sometimes called cricopharyngeus muscle)
exert a sphincteric effect on lower end of pharynx
 prevent entry of air into esophagus btw the acts of swallowing.

Clinical Notes
• The pharyngeal plexus which supplies the muscles is made up from fibres
travelling in the vagus n (pharyngeal branch)
• However, these fibres originate from cranial part of accessory n
• Lesion of vagus n  paralysis of constrictors
• Thus the patient may have difficulty swallowing

74
Nasopharynx
• The phaynx extends from base of skull down to lower border of cricoid cartilage
(opposite CV6), where it becomes continuous with the esophagus
• It can be divided into 3 parts
nasophaynx bhd nasal cavity
oropharynx bhd oral cavity
laryngopharynx bhd larynx

Nasopharynx: Introduction
• lies bhd the nasal cavities, above the soft palate
Thus sometimes regarded as back part of nasal cavity
• when swallowing, soft palate is raised & post pharyngeal wall drawn forward
 nasophaynx is shut off from oropharynx
• nasopharynx has: roof & floor
ant & post walls
lat walls

Roof
• supported by 1. body of sphenoid
2. basilar part of occipital bone
• submucosa of this region contains a collection of lymphoid tissue
= pharyngeal tonsil

Floor
• formed by sloping upper surface of soft palate
• opening = pharyngeal isthmus
- btw free edges of soft palate & post pharyngeal wall
- enables nasopharynx to communicate with oropharynx
- during swallowing, this opening is closed by raising the soft palate
& pulling forward the post pharyngeal wall

Anterior Wall
• formed by post nasal apertures (choanae) separated by post edge of nasal septum
• communicated with nasal cavity anteriorly through the choanae

Posterior Wall
• forms a continuous sloping surface with the roof
• supported by ant arch of atlas

75
Lateral Wall
• opening of auditory tube
tubal elevation post margin of auditory tube forms an elevation
salpingopharyngeal fold salpingopharyngeus muscle (attached to lower
margin of tube)
forms a vertical fold of mucous mbm
pharyngeal recess bhd tubal elevation is a small depression
tubal tonsil bhd opening of auditory tube is a collection of
lymphoid tissue in the submucosa

Blood Supply
asc pharyngeal art (from ECA)

Venous Drainage
venous plexuses below mucosa

Lymphatic Drainage
deep cervical nodes

Nerve Supply
pharyngeal plexus

Clinical Notes
1. infection  hypertrophy of pharyngeal tonsil  enlarged
This is known as adenoids & is removed by adenoidectomy
2. close relationship of infected tonsil to auditory tube may cause deafness
3. nasopharynx may be examined by a mirror passed through the mouth

76
Mechanism of Swallowing
• After food enters the mouth, it is usually broken dwon by the grinding of the teeth
& is mixed with saliva
• The thoroughly mixed food is now formed into a bolus on the dorsum of the
tongue & the process of swallowing begins
• This process has a voluntary & involuntary phase

Voluntary Phase
• ant part of tongue is raised & pressed against hard palate by intrinsic muscles of
the tongue
 pushes bolus of food into post part of oral cavity
• This is followed by styloglossus muscles contracting
 pulls root of tongue upwards & backwards
• palatoglossus also contract
 squeeze bolus of food backward into oropharynx

Involuntary Phase
• elevation of soft palate
pulling forward of post pharyngeal wall by sup constrictors
& contraction of palatopharyngeus
 closure of nasopharyngeal isthmus
ie. nasopharynx closed off from oropharynx
• larynx & laryngeal part of pharynx now elevated
• larynx is closed to prevent entry of food bolus
• the bolus moves downward over the epiglottis & closed entrance of larynx
• reaches lower part of pharynx as result of successive contraction of sup, middle &
inf constrictor muscles & by gravity
• finally, the lower fibres of inf constrictor muscle (cricopharyngeus muscle) relax
 bolus enters the esophagus

Clinical Notes
difficulty in swallowing = dysphagia
- can be caused by paralysis of the constrictors muscles due to lesion of vagus n

77
Auditory Tube
• This is a trumpet-shaped chaneel which connects the nasopharynx with the middle
ear cavity
• Its function is to maintain atm pressure in the middle ear cavity so that the air
pressures on both sides of the tympanic mbm are equal

Length & Direction

• ∼ 3-4 cm long
• extends backward, laterally & upwards from nasopharynx

Parts
post 1/3 = bony
ant 2/3 = cartilaginous
Cartilaginous Part • abt 2-3 cm long, attached to med end of bony part
• lies in a groove btw greater wing of sphenoid & apex of
petrous temporal
• sup & med wall = cartilage
• lat & inf walls = fibrous mbm
• relations
a. anterolat: 1. tensor veli palatini
2. mandibular n
3. middle meningeal art
b. posteromed: 1. levator veli palatini
2. pharyngeal recess
Bony Part • abt 1 cm long
• lies in petrous temporal bone, near tympani plate
• lat end is wider  opens into middle ear cavity
• med end is narrow (isthmus)  attach to cartilaginous part
• relations
a. superiorly 1. canal for tensor tympani
b. anterolat 1. tympanic portion of temporal bone
c. posteromed 1. carotid canal

Mucosal Lining
in cartilaginous part • mainly pseudostr columnar ciliated epith
• contains many mucous glds
in bony part mainly flattened cuboidal non-ciliated epith
= mucoperiosteum

Blood Supply
from: 1. asc pharyngeal
2. middle meningeal
3. art of pterygoid canal

78
Venous Drainage
into: 1. pharyngeal vein
2. pterygoid plexuses of veins

Lymphatic Drainage
into retropharyngeal nodes  deep cervical nodes

Nerve Supply
cartilaginous part by branch from mandibular n
bony part by tympanic plexus (9th n)
Also by pharyngeal branch of pterygopalatine ganglion

Clinical Notes
1. cold / sore throat may lead to inflammation of auditory tube
2. throat infections may be transmitted via the tube to middle ear cavity

79
Middle Ear Cavity
• The middle ear consists largely of an air space
• It is also called the tympanic cavity

Location
• situated in petrous part of temporal bone
• btw ext & int ears

Communications
• with nasopharynx anteriorly via auditory tube
• with mastoid antrum & air cells posteriorly via the aditus to the antrum

Parts
• It consists of
1. tympanic cavity proper which lies opposite the tympanic mbm
2. epitympani recess which lies above the level of the tympanic mbm
• It contains upper part of malleus & greater part of incus

Boundaries
The middle ear has 6 sides
Roof • formed by a portion of petrous temporal called tegmen tympani
(Tegmental Wall) • sep middle ear from middle cranial fossa
Floor • formed by jugular fossa of temporal bone
(Jugular Wall) • sep middle ear from sup bulb of IJV
Anterior • sep middle ear from ICA & symp plexus
(Carotid) Wall • consists of 3 parts 1. opening of canal for tensor tympani sup
2. opening of auditory tube in the middle &
3. post wall of carotid canal inf
Posterior • upper part has large opening = aditus to the mastoid antrum
(Mastoid) Wall • below the aditus is a small projection = pyramid
 contains stapedius muscle
Laterall Wall • sep middle ear from ext acoustic meatus
(Membranous) • formed by tympani mbm below
squamous part of temporal bone above
• above level of tympanic mbm is the epitympanic recess
Medial Wall • sep middle ear from int ear
(Labyrinthine) • this wall presents the following features from above downwards:
1. prominence of lat semicircular canal
& prominence of facial n canal
2. oval window (fenestra vestibule) = closed by base of stapes
& processus cochleariformis (a bony prominence above the
window)
3. promontory
- formed by basal turn of cochlea & covered by tympanic plexus
4. fenestra cochleae (round window)
- closed by mucous mbm of middle ear

80
Contents
Contents Remarks
1 3 ear ossicles • malleus
• incus
• stapes
2 ligs of ear ossicles
3 2 muscles tensor tympani
stapedius
4 vsls supplying & draining middle ear
5 nerves chorda tympani
tympanic plexus
6 air
The middle ear is lined by mucous mbm

Blood Supply
1. stylomastoid artery (from ECA)
2. ant tympanic art (from maxillary artery)
3. many smaller vsls contribute

Venous Drainage
1. sup petrosal sinus
2. pterygoid plexus of veins

Lymphatic Drainage
 preauricular & retropharyngeal nods  deep cervical nodes

Nerve Supply
from tympanic plexus which is formed by
1. auriculotemporal n (5th cranial n)
2. tympanic n(9th cranial)
3. auricular branch (10th cranial n)
Note: Also by nerves from symp plexus around ECA

Clinical Notes
1. otoscopic examination of tympanic mbm
2. infection of nasopharynx may spread via auditory tube to middle ear
3. infection of middle ear is called ottis media
This can spread to all its surrounding relations to cause various symptoms

Functional Considerations
1. Sound  Sound waves in middle ear cavity  tympanic mbm vibrates
 ossicles vibrate  stapes cause vibration of fenestra vestibuli
2. fenestra cochleae vibrates in opposite direction
Thus, sound vibrations are transmitted into inner ear by:
1. auditory ossicles & fenestra vestibuli
2. air in tympanic cavity & fenestra cochleae
3. bone conduction
Disease = otosclerosis of med wall

81
Pterygopalatine Fossa
small pyramidal space bhd & below orbital cavity

Boundaries
ant post surface of maxilla
post greater win of sphenoid & root of pterygoid process
med upper part of perpendicular plate with orbital & sphenoidal processes
with palatine bone
lat open (pterygomaxillary fissure)
sup body of sphenoid
inf pyramidal process & palatine bone

Communications
relations communicates with through
ant orbit inf orbital fissure
post 1. middle cranial fossa foramen rotundum
2. pterygoid canal foramen lacerum
3. pharynx palatovaginal canal
med nose sphenopalatine foramen
lat infratemporal fossa pterygomaxillary fissure
inf oral cavity a. greater palatine canals
b. lesser palatine canals

Contents
1. Maxillary art – 3rd part & branch
2. Maxillary nerve & 2 branches (zygomatic, post alveolar)
3. Pterygopalatine ganglion & branches containing from which maxillary n
mixed with autonomic n

82
Cutaneous Innervation of Face
• skin of face supplied by branches of the 3 divisions of the trigeminal n
except for the small area over the angle of mandible and the parotid gld
which is supplied by the great auricular n
• The overlap of the 3 divisions of the trigeminal n is slight in comparision to the
considerable overlap of adj dermatomes of the trunk and limbs

Embryological Development
ophthalmic n region dev from the frontonasal process
maxillary n region dev from the maxillary process of the
1st pharyngeal arch
mandibular n region dev from the mandibular process of the
1st pharyngeal arch

Ophthalmic Nerve
• supplies the skin of the forehead, upper eyelid, conjunctiva and side of the nose
down to and including the tip
Branches Course Supply
lacrimal n 1. skin
2. conjunctiva of lat upper eyelid
supraorbital n winds around the upper 1. skin
margin of the orbit at the 2. conjunctiva on the central part of
supraorbital notch upper eyelid
3. skin of the forehead
supratrochlear n winds around the upper 1. skin
margin of the orbit 2. conjunctiva on the med part of the
medial to the supraorbital upper eyelid
n 3. skin over the lower part of forehead
close to the median plane
infratrochlear n leaves orbit below the 1. skin
pulley of the sup oblique 2. conjunctiva on med part of the
musc upper eyelid
3. adjoining part of the side of the
nose
ext nasal n leaves nose by emergeing skin on side of nose down to the tip
btw nasal bone and upper
nasal cartilage

83
Maxillary Nerve
• supplies the skin on the post part of the side of the nose, the lower eyelid, the
cheek, the upper lips, and the lat side of the orbital opening
Branches Course Supply
infraorbital n • direct continuation of maxillary n 1. skin of lower eyelid
• enters orbit and appears on the and cheek
face through the infraorbital 2. skin of side of nose
foramen 3. skin of upper lip
zygomatico- passes onto the face through a small skin over the prominence
facial n foramen on the lat side of the of cheek
zygomatic bone
zygomatico- emerges in the temporal fossa through skin over the temple
temporal n a small foramen on the post surface of
zygomatic bone

Mandibular Nerve
• supplies skin of the lower lip, the lower part of the face, the temporal region and
part of the auricle
• then passes upwards to the side of the scalp
Branches Course Supply
mental n emerges from the mental skin of the lower lip and
foramen of the mandible chin
buccal n emerges from beneath the ant skin over a small area of the
border of the masseter musc cheek
auriculotemporal n asc from the upper border of the 1. skin of the auricle
parotid gld btw the supf 2. ext auditory meatus
temporal vsls and the auricle 3. outer surface of the
tympanic mbm
4. skin of the scalp above
the auricle

84
Glossopharyngeal Nerve (9th Cranial Nerve)
• motor and sensory nerve
motor fibres stylopharyngeus
psymp secretomotor fibres parotid salivary gld
sensory fibres (including taste fibres) post 1/3 of tongue & pharynx

Course
• emerges from ant surface of upper MO
by 3 or 4 rootlets along the groove btw olive & inf cbllar penduncle
• passes forward & lat beneath cbllm in post cranial fossa
• leaves skull by passing downward thru central part of jugular foramen
• desc in the neck within the carotid sheath
• winds forward around the stylopharyngeus musc
& passes btw the sup & middle constrictor musc
• lingual branch of n enters the submandibular region

Branches
Branch Course Supply
tympanic br • arises below jugular foramen • lining of tymp cavity
• passes thry floor of tymp cavity • gives off lesser petrosal n
• grooves surface of promontory (with secretomotor fibres
• splits into branches  tymp for parotid gld)
plexus
carotid br carotid sinus & carotid body
musclular br stylopharyngeus musc
pharyngeal br • unite on outer surface of middle sensory fibres to
constrictor musc with pharyngeal 1. mucous mbm of pharynx
br of vagus & pharyngeal br of 2. tonsil
symp trunk 3. soft palate
 pharyngeal plexus
lingual br enters tongue below styloglossus general sensory & special
musc taste fibres to
1. mucous mbm of post 1/3
of tongue
2. circumvallate papillae
region of ant tongue

85
Vagus Nerve (10th Cranial Nerve)
• composed of both motor and sensory fibres

Origin
• originates in MO
• leaves the skull thru middle of the jugular foramen tog with 9th & 11th cn

Sensory Ganglia
Superior Ganglion • rounded
• on n within the jugular foramen
Inferior Ganglion • cylindrical
• lies on n just below foramen
• below this ganglion, cranial part of acc n joins the vagus n
and is distributed mainly in its pharyngeal and recurrent
pharyngeal br

Course in the Neck

• passes vertically down the neck within the carotid sheath
• lies at 1st btw the IJV & ICA
• and then btw IJV and CCA
• At root of the neck accompanies the CCA
& lies ant to 1st part of the subclavian art

86
Branches of Vagus Nerve in the Neck
Branches Ganglion Course Supply
Inv
Meningeal sup dura mater in post fossa of
br ganglion skull
Auricular sup • passes through bony canal of • med surface of auricle
br ganglion skull to emerge bhd the EAM • floor of EAM
• adj part of tymp mbm
pharyngeal inf • passes forward btw the ICA & • all the musc of pharynx
br ganglion, ECA to reach the pharyngeal (except
contains wall stylopharyngeus, by IX)
motor • joins branches from the IX n & • all musc of soft palate
fibres fr symp trunk to form the (except tensor veli
cranial pharyngeal plexus palatini, by mandibular
part of division of V cn)
acc n
sup inf • runs downward & medially bhd
laryngeal n ganglion ICA
• divides into int & ext laryngeal
n
inf • pierces thyrohyoid mbm (with • sensory n
laryngeal n int laryngeal art) • floor of piriform fossa
• mucous mbm of larynx
down to vocal folds
ext • desc tog with sup thyroid gld • cricothyroid musc
laryngeal n • passes deep to thyroid gld
2/3 cardiac • arise from vagus as it desc thru
br neck
• join or accompany cardiac br of
symp trunk
• end in cardiac plexus in thorax
R recurrent • arises from vagus as it crosses • all musc of larynx
laryngeal n 1st part of subclavian art except cricothyroid
• hooks backward & upward bhd • mucous mbm of larynx
art below vocal folds
• asc in groove btw trachea & • mucous mbm of upper
esophagus par of trachea
• passes deep to lobe of thyroid
gld & comes close to inf
thyroid art
• crosses either in front of or bhd
art or may pass btw its branches
• passes beneath lower border of
inf constrictor musc
L recurrent • arises from vagus as it crosses
laryngeal n arch of aorta in thorax
• hooks around beneath arch bhd
lig art
• asc into neck in groove btw
trachea & esophagus

87
Accessory Nerve (11th Cranial Nerve)
• composed of motor fibres

Origin
• formed by union of cranial & spinal roots
• cranial root is smaller & arises in the MO
• spinal roots arise from C1-C5 segments of sp cord

Course in Neck
• spinal roots unite to form a trunk that asc in vertebral canal to enter the skull
through foramen magnum
• Both the cranial & spinal roots come tog & pass through the middle of jugular
foramen

Course of Cranial Root

• sep from sp root & joins the vagus at inf ganglion
• distributed mainly in the pharyngeal & recurrent laryngeal branches

Course of Spinal Root

• runs downward & lat & crosses the IJV
• then enters the deep surface of sternocleidomastoid, which it supplies
• emerges above the middle of post border of sternocleidomastoid & crosses the
post triangle of neck on the lev scap to supply the trapezius musc

88
Hypoglossal Nerve (12th Cranial Nerve)
motor nerve to tongue muscles

Origin
arises in MO

Course
• leaves the skull thru hypoglossal canal in the occipital bone
• comes in close relationship with 9th, 10th, & 11th cn, ICA and IJV
• desc btw ICA & IJV until it reaches the lower border of post belly of digastric
musc
• runs forward & med
• nerve loops around occipital art & crosses ICA & ECA & loop of ligual art
(just above tip of greater cornu of hyoid bone)
• passes forward & upward, deep to digastric, stylohyoid, post margin of mylohyoid
musc
• in upper part of its course, joined by small br from cervical plexus
(C1 & sometimes C2)
This br later leaves XII n as its desc br
n to thyrohyoid
n to geniohyoid
• Runs forward on lat surface of hyoglossus musc
& on med surface of mylohyoid musc
• lies below deep part of submandibular gld, submandibular duct & lingual n
• ends by curving upward toward tip of tongue

Branches in Neck
Branches Origin & Course Supply
Meningeal Br • arises fr n as it traverses the meninges in post cranial
hypoglossal canal fossa
Desc Br • arises fr n as it curves forward Branches of loop:
(C1 fibres) below the post belly of digastric omohyoid
• desc in front of ECA & CCA, sternohyoid
within carotid sheath sternothyroid
• joined by desc cervical n (C2 & 3)
fr cervical plx to form a loop (ansa
cervicalis)

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Branches in Tongue
Branches Origin & Course Supply
n to thyrohyoid • arises fr n as it passes deep to thyrohyoid musc
(C1 fibres) mylohyoid musc
n to geniohyoid • given off on side of tongue geniohyoid musc
(C1 fibres)
Communicating br with lingual n on side of tongue
• Also muscular branches to all musc of tongue
except palatoglossus (by pharyngeal plexus)
• Thus supplies styloglossus
hyoglossus
genioglossus
intrinsic musc of tongue

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Paranasal Sinuses
• cavities fd in int of maxilla, frontal, sphenoid & ethmoid bones
• lined with mucoperiosteum, filled with air
• communicate with nasal cavity thru small apertures

Mucous Membrane
• have glds which produces mucus
• mucus moved by ciliary action of columnar cells
• drainage of mucus: by siphon action created by blowing of nose

Function
1. act as resonators to voice
2. reduce weight of skull
Thus when sinuses blocked, or filled with fluid, quality of voice changed

Maxillary Sinus
• found within body of maxilla
• pyramidal in shape
base forms lat wall of nose
apex in zygomatic process of maxilla
roof formed by floor of orbit
floor formed by alveolar process
• Roots of 1 & 2nd premolars & 3rd molar & sometimes, root of canine, project up
st

into max sinus

• opens into middle meatus of nose thru hiatus semilunaris
• clinically: - opening of max sinus to middle meatus is high
 sinus accumulates fluid
- frontal & ant eth sinuses drain into infundibulum, into hiatus
 infection from these sinuses may spread to max sinus
• nerve supply of mucous mbm: sup alveolar n
infraorbital n

Frontal Sinuses
• contained within frontal bone
• separated from each other by bony septum (freq deviated from median plane)
• roughly triangular in shape - extend upward above med end of eyebrow
backward into med part of roof of orbit
• opens into middle meatus of nose thru infundibulum
• nerve supply of mucous mbm: supraorbital n

Sphenoidal Sinuses
• lie within body of sphenoid bone
• opens into spenoethmoidal recess above sup concha
• nerve supply of mucous mbm: post ethmoidal n

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Ethmoidal Sinuses
• contained within ethmoid bone (btw nose & orbit)
• sep from orbit by thin plate of bone
 infection can spread from sinuses into orbit
• divided into 3 groups: ant, middle, post
Sinus ant gp middle gp post gp
Opening infundibulum middle meatus sup meatus
• nerve supply of mucous mbm: ant & post ethmoidal n

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Oral Cavity
Extent
from lips to oropharyngeal isthmus (jn of mouth with pharynx)

Subdivision
• vestibule - Externally: lies btw lips & cheeks
Internally: lies btw gums & teeth
• Mouth cavity proper: lies within alveolar arches, gums & teeth

Vestibule
• slit-like space that communicates with
1. the ext thu oral fissure
2. mouth proper bhd the 3rd molar tooth on each side when jaws are closed
• Boundaries
Sup & inf limited by reflection of mucous mbm
from lips & cheeks onto gums
laterally cheek
(made up of buccinator musc, covered ext
by buccopharyngeal fascia & skin &
lined by mucous mbm)
• Papilla opposite upper 2nd molar tooth on the mucous mbm
= opening of duct of parotid salivary gld

Mouth Proper
Roof In front: hard palate
Behind: soft palate
Floor • ant 2/3 of tongue
• reflection of mucous mbm from sides of tongue to
gum on mandible
Midline frenulum of tongue (fold of mucous mbm)
connects the undersurface of tongue to floor of mouth
• duct of submandibular gld: summit of small papilla
on each side of frenulum
• Sublingual fold - prod by underlying sublingual gld
- a rounded ridge of mucous mbm
extends backward & laterally from papilla

Sensory Nerve Supply of Mucous Mbm of Mouth

Supply
Roof greater palatine & nasopalatine n
n fibres travel in max n
Floor lingual n (br of mand n)
taste fibres travel in chorda tympani n (br of facial n)
Cheek buccal n (br of mand n)

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Palate
• forms roof of mouth
• divided into 2 parts: 1. hard palate in front
2. soft palate behind

A. Hard Palate
• formed by 1. palatine processes of maxillae
2. horizontal plates of palatine bones
• forms floor of nasal cavities
• undersurface: mucoperiosteum
with a median ridge (on either side, corrugated mucous mbm)
Boundary
• alveolar arches
• bhd, continuous with soft palate

Mucous Mbm: - covered by str sq epith

- post, numerous mucous glds

B. Soft Palate
• mobile fold attached to post border of hard palate
• sides – continuous with lat wall of pharynx

Contents
• aponeurosis, muscle fibres, lymphoid tissue, glds, vsls & n
• uvula – midline conical projection on post border
• composed of
1. mucous mbm - covers upper & lower surface of soft palate
- covered mainly with str sq epith
- numerous mucous glds present on both surfaces
- submucosa: collections of lymphoid tissue
2. palatine aponeurosis
- fibrous sheet attached to post border of hard palate
- expanded tendon of tensor veli palatini
& splits to enclose the musculus uvulae
3. muscles: a) tensorveli palatini
b) levator veli palatini
c) palatoglossus
d) palatopharyngeus
e) musculus uvulae

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Movements
Raise soft palate
- to close the pharyngeal isthmus,
to close off nasal part of pharynx from oral part
(communicating channel btw nasal & oral parts of pharynx)
- occurs during production of explosive consonants in speech
- by contraction of 1. lev veli palatini on each side
2. upper fibres of sup constrictor musc
 pull post pharyngeal wall forward
3. palatopharyngeus musc on both sides
 pull palatopharyngeal arches medially

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Pharynx
• situated bhd the nasal cavities, the mouth, & the larynx
• funnel-shaped: upper, wide end under skull
lower, narrow end becoming continuous with esophagus
opposite CV6
• musculomembranous wall - def ant
- here replaced by
1. post nasal apertures
2. oropharyngeal isthmus (opening into mouth)
3. inlet of larynx
• can be divided into 3 parts
nasopharynx bhd nasal cavity
oropharynx bhd oral cavity
laryngopharynx bhd larynx
• wall has 3 layers – mucous, fibrous, muscular

Mucous Membrane
• continuous with that of 1. nasal cavities
2. mouth
3. larynx
4. tympanic cavity (by auditory tubes)
• upper part: ciliated columnar epith
lower part: str sq epith
transitional zone – where the 2 areas come tog

Fibrous Layer
• lies btw mucous mbm & muscle layer
• Above: thicker (strongly connected to base of skull)
Below: continuous with submucosal coat of esophagus

Muscular Layer
1. sup constictor muscle
2. middle constrictor muscle fibres run in > or < circular direction
3. inf constrictor muscle
4. stylopharyngeus fibres run in a > or < longitudinal direction
5. salpingopharyngeus

Nerve Supply
mainly from pharyngeal plexus (br of glossopharyngeal, vagus & symp n)
Motor Nerve Supply Sensory Nerve Supply (to mucous mbm)
• from cranial part of acc n nasopharynx: max n
(via br of vagus to pharyngeal pl) oropharynx: glossopharyngeal n
• supplies all muscles of pharynx around entrance: int laryngeal br of vagus
except stylopharyngeus (by IX n) n into larynx

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Arterial Supply
from br of 1. asc pharyngeal art
2. asc palatine art
3. facial art
4. max art
5. lingual art

Venous Drainage
into pharyngeal venous plexus (into IJV)

Lymphatic Drainage
LV from pharynx drain either
1. directly into deep cervical LN
2. indirectly via retropharyngeal or paratracheal nodes

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Oropharynx
• lies bhd the mouth cavity
• extends from soft palate to upper border of epiglottis
• has roof & floor
ant & post wall
lat wall

Roof
• formed by undersurface of soft palate & pharyngeal isthmus
• small collections of lymphoid tissue present in submucosa on undersurface of soft
palate

Floor
• formed by 1. post 1/3 of tongue (almost vertical)
2. interval btw tongue & ant surface of epiglottis
• mucous mbm on post 1/3 of tongue
- devoid of papillae
- irregular in appearance (due to presence of underlying lingual tonsil)
- reflected from tongue onto epiglottis
• median glossoepiglottic fold - midline elevation
- on each side is vallecula (depression)
2 lat glossoepiglottic folds

Anterior Wall
• opens into mouth thru the oropharyngeal isthmus
• below this opening – pharyngeal part of tongue

Posterior Wall
supported by 1. the body of CV2
2. upper part of body of CV3

Laterall Walls
consists of 1. palatoglossal & palatopharyngeal arches or folds
2. tonsillar sinus (triangular recess) containing the palatine tonsils
1. Palatoglossal arch
• fold of mucous mbm covering underlying palatoglossus muscle
• interval btw 2 palatoglossal arches is the oropharyngeal isthmus
(boundary btw mouth & oral pharynx)
2. Palatopharyngeal arch
• fold of mucous mbm on lat wall of oropharynx bhd palatoglossal arch
• covers underlying palatopharyngues muscle

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3. Palatine Tonsils
• 2 masses of lymphoid tissue located in lat walls of oropharynx in tonisllar sinuses
• covered by mucous mbm
• free med surface - proj into cavity of pharynx
- surface pitted by numerous small openings
(lead into tonsilar crypts)
- upper part has a deep intratonsillar cleft
• lat surface covered by capsule (layer of fibrous tissue)
• reaches max size during early childhood
but after puberty diminished in size considerably
• relations
ant palatoglossal arch (may extend for short dist beneath)
post palatopharyngeal arch
sup soft palate
- here, tonsil becomes continous with lymphoid tissue on
undersurface of soft palate
inf post 1/3 of tongue
- here, tonsil becomes continuous with lingual tonsil
med cavity of oropharynx
lat 1. capsule separted from
2. sup constrictor musc by loose areolar tissue
3. ext palatine vein desc from soft palate in the LCT to join
pharyngeal venous pl
4. styloglossus & loops of facial art (lat to sup constrictor musc)
5. ICA lies 1 inch bhd & lat to tonsil
• art supply: tonsilar art (br of facial art)
• veins - pierce sup constrictor musc
& join the ext palatine, the pharyngeal or facial veins
• LV - join upper deep cervical LN
esp jugulodigastric node (below & bhd angle of mandible)

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Laryngopharynx
• lies bhd opening into larynx & post surface of larynx
• extends btw upper border of epiglottis & lower border of circoid cartilage
• has ant wall & post wall
lat wall

Anterior Wall
formed by 1. inlet of larynx
2. mucous mbm covering post surface of larynx

Posterior Wall
supported by bodies of CV3, 4, 5, 6

Lateral Wall
• supported by thyroid cartilage & thyrohyoid mbm
• piriform fossa - groove in mucous mbm on each side of laryngeal inlet
- lead obliquely downward & backward
from region of back of tongue to esophagus
- bounded med: aryepiglottis fold
lat: lamina of thyroid cartilage &
thyrohyoid cartilage

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External Ear
• consists of auricle & ext auditory meatus
• outer 1/3: elastic cartilage
inner 2/3: bone (tympanic mbm)
• lined by skin
• outer 1/3 has: 1. hairs
2. sebaceous glds
3. ceruminous glds - modified sweat glds
- secrete yellowish-brown wax
hairs & wax provide sticky barrier that prevents the entrance of foreign bodies

Auricle
• characteristic shape
• serves to collect air vibrations
• consists of a thin plate of elastic cartilage covered by skin
• has both extrinsic & intrinsic muscles (supplied by facial n)

External Auditory Meatus

• sinuous tube that leads from auricle to tympanic mbm
• Fn: to conduct sound waves from the auricle to the tympanic mbm
• isthmus narrowest (abt 5 mm from tympanic mbm)
• anteroinf wall longest (because of obliquity of tympanic mbm)

Sensory Nerve Supply to lining skin

from 1. auriculotemporal n
2. auricular br of vagus n

Lymphatic Drainage
to 1. supf parotid LN
2. mastoid LN
3. supf cervical LN

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Larynx
• provides a protective sphincter at the inlet of air passages
• responsible for voice production
• above: opens into laryngopharynx
below: continuous with trachea
• framework: cartilages connected by mbms & ligs, moved by muscles
• lined by mucous mbm

Cartilages
thyroid • 2 laminae of hyaline cartilage meeting in midline (in prominent V
cartilage angle of Adam’s apple)
• post border of each lamina is drawn upward  sup cornu
downward  inf cornu
• oblique line - on outer surface of each lamina
- for attachment of sternothyroid
thyrohyoid
inf constrictor musc
cricoid • formed from complete ring of hyaline cartilage
cartilage • signet ring shape
• lies below thyroid cartilage
• consists of narrow ant arch
broad post lamina
• side of lat surface – circular articular facet  inf cornu of thyroid
cartilage
• side of upper border – articular facet  base of arytenoid cartilage
(all joints are synovial joints)
arytenoid • 2, small pyramidal
cartilage • fd at back of larynx on lat part of upper border of lamina of cricoid
cartilage
• consists of apex - above
- supports corniculate cartilage
base - below
- articulates with cricoid cartilage
- projects 2 processes
1. vocal process
- proj horiz forward
- gives attachment to vocal lig
2. muscular process
- proj lat
- gives attachment to post &
lat cricoarytenoid musc
corniculate • 2 small nodules
cartilage • articulate with apices of arytenoids cartilages
• give attachment to aryepiglottic cartilages
cuneiform • 2 small, rod-shaped pieces of cartilage
cartilage • placed one in each aryepiglottic fold
• serve as supports for the folds

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epiglottis • leaf shaped elastic cartilage
• fd bhd root of tongue
• connections:
1. in front – body of hyoid bone
2. by stalk – back of thyroid cartilage
3. sides – arytenoid cartilages by aryepiglottic folds
• upper edge - free
- covering of mucous mbm
reflected forward onto post surface of tongue
 median glossoepiglottic fold
lateral pharyngoepiglottic folds
valleculae (depressions of mucous mbm on
either side of glossoepiglottic folds)

Membranes & Ligaments of the Larynx

thyrohyoid • connects
membrane upper margin of thyroid cartilage below to
upper margin of post surface of body & greater cornu of
hyoid bone above
• medaian thyrohyoid lig – mbm thickened in midline
• lat thyrohyoid lig – thickened post borders
• pierced by sup laryngeal vsls & int laryngeal n on each side
cricotracheal • connects lower margin of cricoid cartilage to
ligament 1st ring of trachea
fibroelastic • beneath mucous mbm lining the larynx
membrane of • quadrangular mbm - upper portion of mbm
larynx - extends btw epiglottis & arytenoid cartilages
• cricothyroid lig - lower part of mbm
- ant part thick;
connects cricoid lig to
lower margin of thyroid cartilage
- lat part is thin,
attached below to upper margin of cricoid catilage
- sup margin asc within thyroid cartilage on its med
surface
- upper margin thickened
formes impt vocal lig on each side
vocal lig – ant end  deep surface of thyroid
cartilage
– post end  vocal process of the
arytenoid cartilage
hypoepiglottic attaches to epiglottis to hyoid bone
ligament
thryoepiglottic attached to epiglottis to thyroid cartilage
ligament

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Inlet of Larynx
• looks backward & upward into laryngopharynx
• boundaries of opening
in front upper margin of epiglottis
lat aryepiglottic fold of mucous mbm
- connects epigloittis to arytenoid cartilage
posteroinf • mucous mbm stretching btw arytenoid cartilages
• corniculate cartilage (on apex of arytenoid cartilage) &
cuneiform cartilage (small bar) produce
a small elevation on upper border of each aryepiglottic fold

Cavity of the Larynx

• extends from inlet to lower border of cricoid cartilage
• may be divided into 3 parts: 1. upper part = vestibule
2. middle part
3. lower part

1. Vestibule of Larynx
• extends from inlet to vestibular folds
• vestibular folds – 2 thick folds of mucous mbm that cover vestibular lig
• has ant, post & lat wall
ant wall post surface of epiglottis (covered by mucous mbm)
post wall arytenoid cartilages &
interarytenoid fold of mucous mbm (containing tnvs arytenoid musc)
lat walls aryepiglottic folds (contain the aryepiglottic musc)
• below, narrowed by pink vestibular folds (proj medially)
rima vestibuli - gap btw vestibular folds
vestibular lig - lies within each vestibular fold
- thickened lower edge of quadrangular mbm
- stretches from thyroid cartilage to side of arytenoid cartilage

2. Middle Part of Larynx

• extends from level of vestibular folds to level of vocal folds
• vocal folds - white in colour
- contain vocal lig
vocal lig - thickened upper edge of cricothyroid lig
- stretches from
thyroid cartilage in front to
vocal processes of arytenoid cartilage bhd
• rima glottis – gap btw vocal folds in front &
vocal processes of arytenoids cartilage bhd
• sinus of larynx - small recess btw vestibular & vocal folds on each side
- lined with mucous mbm
- diverticulum from mucous mbm: saccule of the larynx
 passes upward btw vestibular fold & thyroid cartilage

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3. Lower Part of Larynx
• extends from the level of vocal folds to lower border of cricoid cartilage
• walls formed by inner surface of cricothyroid lig & cricoid cartilage

Mucous Membrane
• lines cavity
• covered with ciliated columnar epith
• on vocal folds: covered with str sq epith
 mucous mbm subject to repeated trauma during phonation
• mucous glds within mucous mbm, esp in saccules
where secretion pours down onto upper surface of vocal folds & lubricates them
during phonation

Nerve Supply
Sensory n supply
to mucous mbm of larynx
a) above vocal folds int laryngeal br of sup laryngeal br of vagus
b) below level of vocal folds recurrent laryngeal n
Motor n supply
to intrinsic musc of larynx recurrent laryngeal n
Note: except for cricothyroid musc.
 by ext laryngeal br of sup laryngeal br of
vagus

Blood Supply
upper 1/2 of larynx: sup laryngeal br of sup thyroid art
lower 1/2 of larynx: inf laryngeal br of inf thyroid art

Lymphatic Drainage
LV drain into deep cervical group of nodes

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