The Skull

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Introduction
Skull =cranium and face bone
Formed by two sets of bones
8 cranial bones (calvaria/cranium) – enclose brain
•
• 14 facial bones - forms face
These 22 bones combine to form the cranial cavity and
the facial features
Most bones of the skull are flat bones
Except for the mandible, all bones are firmly united by
interlocking sutures

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 Functions
The bones of the skull provide
• a case to house the brain, the cranium
• a framework for the face
• cavities to house the organs of sight, taste, hearing and
smell
• passages for air and food
• attachment sites for the teeth
• attachment sites for muscle
Position of the skull in erect posture:
the lower margin of the orbit and the upper margin of the
external acoustic meatus must be on the same horizontal plane
(eye-ear plane)
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 Cranial Base
 Cranial base forms the
skull’s inferior aspect
 Three prominent ridges
divide the base into
fossae
 The brain rests on these
cranial fossae completely
enclosed by the cranial
vault
 The brain occupies the
cranial cavity

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 Cavities of the Skull
In addition to the large cranial cavity there are many
smaller cavities
 Middle and inner ear cavities
 Nasal cavity
 Orbits for the eyes
 Several bones contain air filled sinuses
 Sinuses surround the nasal cavity thus referred
to as the paranasal sinuses

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 Cranium

Composed of eight flat bones surrounding and

protecting the brain
 Paired - parietal and temporal
 Unpaired - frontal, occipital, sphenoid and ethmoid

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Frontal bone
Forms the anterior
portion of the
cranium; the forehead,
roofs of the orbits,
and most of the
anterior cranial fossa
Parts
 Zygomatic process
 Orbital plate: forms
anterior cranial fossa
 Frontal squama: forms
forehead, in fetal skull
right and left halves
are fused by metopic
suture
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Frontal bone: bone markings
 Supraciliary arches - above the medial part of the orbit
 Supraorbital notch (foramen) - transmit supraorbital nerve and
vessels
 Supraorbital margin - thickening above orbits; from this margin,
frontal bone extends posteriorly to form roof of orbit
 Glabella
 Nasion
 Frontal sinuses
 Sutures - coronal, frontonasal, frontomaxillary, zygomaticofrontal

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Parietal bones
Forms most of the superior & lateral aspects of the skull
Articulates with other cranial bones to form three major
sutures
 Coronal
 Lambdoid
 Parietotemporal
Articulates with each
other at Sagittal suture

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 Bones of the Skull

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General features
Two curved lines on lateral surface
Superior and inferior temporal lines - gives attachment of
epicranial aponeurosis, temporal fascia and temporalis muscle
Landmarks
Emissary foramen; located at the posterior end of the
sagittal suture (2-4 cm anterior to the lambdoid
suture )
It connects the veins of the scalp with superior sagittal sinus

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Occipital bone
Forms most of the posterior wall and base of skull
Articulates with parietal, temporal and the first cervical
vertebrae
Bound foramen magnum
Parts
 Squamous
 basilar
Sutures- lambdoid, occipitomastoid, sagittal

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 Occipital bone: landmarks
Foramen magnum – large oval opening;
communicate cranial cavity with vertebral canal
Occipital condyles – oval processes on either side
of foramen magnum; articulate with atlas to form
atlanto-occipital joint
External occipital protuberance – midline
projection posteriorly
Nuchal lines
Superior nuchal line - runs laterally from external
occipital protuberance. It is a boundary between scalp
and neck
Inferior nuchal line - runs laterally form the mid
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point of the external occipital crest
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 Temporal Bone
Forms
 Inferolateral
aspects of the
skull
 Parts of the
cranial floor
Divided into four
regions
 Squamous
 Tympanic
 Mastoid
 Petrous
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 Temporal Bone: Squamous part
Anterior and superior part
Zygomatic process: projection from inferior part;
meets the zygomatic bone to form zygomatic arch
Zygomatic arch - formed by the union of processes
of the temporal and zygomatic bone; attachment
for masseter, temporal fascia and lateral ligament
of temporomandibular joint
Mandibular fossa – inferiorly, receives condyle of
mandible to form temporomandibular joint

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 Temporal Bone: Mastoid part
Posterior and inferior to ear canal
Contains mastoid air cells
Mastoid process - point of attachment for muscles of
neck
Mastoid foramen – transmit emissary vein, connects
the sigmoid sinus with occipital and posterior
auricular veins. It transmits also meningeal occipital
artery.
Styloid process - attachment for stylopharyngeus,
stylohyoid and styloglossus muscles and ligaments -
stylohyoid and stylomandibular
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 Temporal Bone: Tympanic part
Contains external acoustic meatus
Temporal Bone: Petrous part
Contributes to the cranial floor; with sphenoid bone
form the middle cranial fossa
Houses internal and middle ear
Contains carotid foramen
Landmarks
Jugular foramen: entry point for the internal jugular vein
Internal acoustic meatus: entry point for the auditory nerve
Stylomastoid foramen: exit for facial nerve
Carotid canal: entrance for the carotid artery

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Sphenoid bone

Bone spanning the width of middle cranial

fossa
Resembles bat with stretched wings
Articulates as central wedge with all cranial
bones
Parts
Consists of central body and three processes;
greater and lesser wings and pterygoid
process
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 Body
cube shaped medial portion
superior surface is termed as Sella turcica
 tuberculum sellae – anterior horn
 hypophyseal fossa - for pituitary gland
 dorsum sellae – posterior horn
contain sphenoidal sinuses
Greater wings
forms anterolateral floor and lateral wall of middle cranial cavity
Lesser wings
forms part of posterior floor of anterior cranial cavity and part of
orbit
Pterygoid Processes - medial and lateral pterygoid plates
which extends inferiorly from the junction of body and
greater wings
Pterygoid fossa - V shaped space b/n the two pterygoid plates
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 Foramina
Optic foramina – between body and lesser wing
Superior orbital fissure – between greater and lesser wings
Foramen rotundum, ovale and spinosum on greater wing

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Ethmoid bone
 Forms anterior part of
cranial floor, medial wall
of orbit, superior portion
of nasal septum and
superior side wall of
nasal cavity
 Lies between nasal
bones & sphenoid
 Forms most of the area
between the nasal cavity
& orbits of eyes
 Complex shape gives
rise to nasal septum,
sinuses and cribiform
plate

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 Ethmoid bone: parts
Lateral mass
contain ethmoidal sinuses
forms superior and middle nasal conchae
 Project into nasal cavity
Middle part
Perpendicular plate
 Forms superior part of nasal septum
Cribiform plates
 Forms roof of nasal cavity
 Contains olfactory foramina for olfactory nerves
Crista galli
 Project up ward from cribriform plate
 Attachment of the dura mater
Orbital plates
 Forms medial walls of orbits

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 Facial bones
Consists of 14 bones
Paired - maxilla, zygomatic, palatine, nasal,
lacrimal, inferior nasal conchae
Unpaired - mandible and vomer

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Nasal bones
Forms bridge of the nose
Thin, rectangular shape
Fused medially
Articulate with the frontal bone and maxillary bones
laterally and with nasal cartilages

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Mandible
Forms the lower jaw
Largest, strongest bone of the face
the only movable bone of the skull
Houses lower dentition
Two parts - the body and the two rami

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 Mandible: body
Curved, horizontal portion
Two surfaces: external and internal
Two boarders: upper and lower
External surface
Symphysis menti - between right and left parts, ossify at the
end of the first month of postnatal period, at birth the right
and the left halves are connected by fibrocartilage
Mental protuberance- triangular area below the symphysis
Mental tubercle- on each side of the base of the protuberance
Oblique line- directs back ward and up ward from mental
tubercle to the anterior boarder of the ramus
Mental foramen - below the interval b/n the 1st and 2nd
premolar; transmit mental nerve and vessels
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 Internal surface
Four genial tubercles - two superior and two
inferior
Mylohyoid line - from inferior genial tubercle to
behind the last molar teeth; directs up and backward
Submandibular fossa - below the mylohyoid line
Sublingual fossa- above mylohyoid line
Upper (alveolar) boarder - contains 16 and 10
sockets in adults and children respectively
Lower boarder- forms the base of the mandible

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 Mandible: Ramus
Perpendicular portion
Medial surface - mandibular foramen, lingula, mylohyoid
groove
Superiorly posses two processes
Coronoid process - the anterior process
Condylar process - the posterior process having two parts, the head
and neck
 Head – articulate with mandibular fossa and articular eminence to form TMJ
 Neck - anteriorly has Pterygoid fossa
Mandibular foramen – entrance to mandibular canal
Mandibular canal - begins at the mandibular foramen, passes
forward and downward, divides into incisive and mental
canal below the 2nd premolar
Communicates with sockets of the teeth
Transmit inferior alveolar vessels and nerve
Dentists use mental and mandibular foramina to inject
anesthetics
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Maxillary bone
Forms upper jaw and central portion of facial skeleton
Surround anterior nasal aperture and unite in medial
plane
Articulates with all facial bones except mandible
Forms upper dentition
Surfaces - nasal, orbital, infratemporal, and anterior
Parts – Body and Four processes - frontal, alveolar,
zygomatic and palatine
Body – houses maxillary sinus

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Frontal process
Forms lateral aspects of nose
articulate with the frontal bone and form the medial wall of the
infraorbital border
Alveolar process - forms socket for maxillary teeth
Zygomatic process - articulates with zygomatic bone and
completes the infraorbital rim
Palatine process
Forms anterior 2/3 of hard palate
presents median palatine suture (between the two palatine
processes of the maxilla) and incisive foramen posterior to the
maxillary central teeth (transmits nasopalatine nerve and vessels)
Foramina
 Infraorbital foramen – transmit Infraorbital nerve and blood vessels to face
 Inferior orbital fissure – between greater wing and maxilla

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Zygomatic bones
Commonly called the cheekbones
Form prominences of cheeks and inferolateral
margins of orbits
Articulate with the frontal, temporal, sphenoidal and
maxillary bones
Three processes - frontal, temporal and maxillary
Foramen - Zygomaticotemporal and
Zygomaticofacial

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Lacrimal Bones
Forms part of the
medial border of
each orbit
Articulates with
frontal, ethmoid &
maxillae
Forms part of
Lacrimal fossa

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Palatine bones
 L- shaped
 Parts

 Horizontal plate
 Forms posterior portion of
hard palate
 Vertical plate
 Forms part of the
posteriolateral walls of nasal
cavity
 Orbital surface
 Forms part of inferior medial
aspect of orbit

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 Vomer
Single,
triangular
bone
Forms part
of the nasal
septum

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 Inferior Nasal Conchae
 Form part of lateral
walls of nasal
cavity
 Project medially
from the lateral
walls of nasal
cavity
 Largest of nasal
conchae
 NB: superior and
middle concha are
on the ethmoid
bone
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 Major Bones of the Skull

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 Pterion
Area at which bones forming the floor of the
temporal fossa articulate (frontal, parietal, temporal
and sphenoid)
H shaped suture
Clinically important landmark because anterior
branch of middle meningeal artery lies in a groove
on internal aspect of this area. Thus, it is vulnerable
to tearing if there is fracture and results in extradural
hematomas which can exert pressure on cerebral
cortex

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 Temporomandibular joint (TMJ)
Articulating surfaces
Head of mandible
Mandibular fossa and articular tubercle of the temporal bone
Type of joint
Modified hinge synovial joint
Articular Capsule
surround the joint
thickened laterally to form ligaments
Articular disc
dividing joint cavity into a lower compartment & upper
compartment
Major supportive elements of the TMJ
muscles of mastication
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 Ligaments of TMJ; Minor supportive of TMJ
Temporomandibular ligament - thickening of the joint
capsule
Stylomandibular ligament - behind and medial
Sphenomandibular ligament - medially attached to the
sphenoid and mandible
Synovial membrane – lines the capsule in the upper
and lower parts the joint cavity
Nerve supply – Auriclotemporal and nerve to
masseter
Arterial supply – from superficial temporal
Relations of TMJ
Posteriorly – external acoustic meatus
Laterally – parotid gland
Medially – maxillary vessels and auriclotemporal nerve

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 Temporomandibular Joint

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 TEMPOROMANDIBULAR JOINT

•Upper (temporomeniscal) joint (ujc): is b/n mandibular

(articular) fossa of the temporal bone & the articular disc  it
provides a sliding motion:
protrusion & retraction movements take place here.
Action of lateral pterygoid
•Lower (meniscomandibular) joint (ljc): is b/n articular disc &
head of the condyle of mandible:
the action here is a hinge-like action :
 depression & elevation movements
Side to side or chewing or grinding movements occur at both
joints

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 Bones of the Skull

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Fractures of calvaria
depressed fractures, in which a bone fragment is depressed
inward, compressing and/or injuring the brain

Linear calvarial fractures, the most frequent type, usually

occur at the point of impact, but fracture lines often radiate
away from it in two or more directions

In comminuted fractures, the bone is broken into several

pieces.

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 Cranial Fractures

Fractures in floor of anterior cranial fossa may

involve the cribriform plate of ethmoid, resulting
in leakage of CSF thru the nose (CSF
rhinorrhea):

 CSF rhinorrhea may be a primary indication

of a cranial base fracture which increases the
risk of meningitis, because an infection could
spread to the meninges from the ear or nose.

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 Dislocation of the jaw
Dislocation of the jaw, occurs in a forward direction.
When the mouth is widely open, the condyloid process of
the mandible slides forward on to the articular eminence;
from thence, a blow, or even a yawn, may cause forward
dislocation into the infratemporal fossa on one or both sides.
Upward dislocation can occur only in association with
extensive comminution of the skull base, and backward
dislocation with smashing of the bony external auditory
canal and tympanic cavity which
 SCALP
A stiff structure coving the skull
Boundaries
Anteriorly- eye brows
Posteriorly- superior nuchal line
Laterally- temporal line

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 The Scalp
•skin of the scalp extends from front
and lateral side of the face into the
occipital region of the skull posteriorly.
•makeup of the scalp is important
clinically because trauma to the scalp
is frequent.

•The scalp is made of 5 layers:

S -- skin
C -- dense connective tissue
A -- aponeurosis of the
occipitofrontalis muscle
L -- loose connective tissue
P -- periosteum
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 The SCALP
The scalp consists of five layers: S, C, A, L, P
 first three are intimately bound together & move as
a unit.
1. Skin, thick, hair-bearing; contains numerous
sebaceous glands.

2. Connective tissue: beneath the skin, which is fibro-

fatty,
fibrous septa uniting skin to underlying aponeurosis
of occipitofrontalis muscle.
Numerous arteries & veins are found in this layer.
The arteries are branches of external & internal
carotid arteries, a free anastomosis takes place b/n them.
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 THE SCALP
 3. Aponeurosis (epicranial): thin tendinous sheet , unites
occipital & frontal bellies of occipitofrontalis muscle.
 4. Loose areolar tissue, occupies the sub­aponeurotic space.
 - loosely connects the epicranial aponeurosis to the periosteum
of the skull (the pericranium) & it is continuous from front to
back.
 - contains a few small arteries, but it also contains some
important emissary veins.
  emissary veins are valveless & connect superficial veins
of scalp with diploic veins of skull bones & with
intracranial venous sinuses.
 5. Pericranium, which is the periosteum covering outer surface
of skull bones.
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 THE SCALP
 The loose areolar tissue layer is the danger area of the scalp
because pus or blood spreads easily in it.
 Infection in this layer can pass into cranial cavity thru emissary veins,
which pass thru foramina in the calvaria & reach intracranial structures
such as meninges (dural venous sinuses).
 An infection of scalp cannot pass into the neck because occipital belly
of occipitofrontalis attaches to occipital bone & mastoid parts of
temporal bones;
 a scalp infection also can not spread laterally beyond zygomatic arches
because epicranial aponeurosis is continuous with temporalis fascia
that attaches to these arches.
 An infection or fluid (e.g., pus or blood) can enter eyelids & root of the
nose because frontal belly of occipitofrontalis inserts into skin & dense
subcutaneous tissue & does not attach to the bone.
Ecchymoses, or purple patches, develop as a result of extravasation of
blood into subcutaneous tissue & skin of eyelids & surrounding regions.
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 The Scalp
 Blood vessels come into scalp from three different regions:
 1). anterior (supratrochlear & supraorbital), 2). lateral
(superficial temporal), 3). posterior (occipital).

 There is free anastomoses of vessels from side to side:

With all of this blood supply, lacerations of scalp are usually
profuse & because of the abundant nerve supply, very sensitive.

 The loose connective tissue layer of scalp will allow bacteria or fluid
to pass freely from posterior aspect of scalp into eyelids in front.
 Trauma in the back of the head can result in blood showing up
in the eyelids ”black eye”  & this should make you suspect
something is going on in the back of the head.

Nerves of Scalp:
 scalp is well supplied with cutaneous nerves - those in front of
the ear come from trigeminal (all 3 parts) & those behind the
ear arise from the ventral & dorsal rami of C2 & C3.

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Scalp Wounds
Scalp Infections

Ecchymosis (extravasation of blood under the

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skin).
 Muscles of the Scalp
OCCIPITOFRONTALIS:
 consists of four bellies, two occipital & two frontal, connected by an
aponeurosis.
Origin:
 Each occipital belly arises from the superior nuchalline of occipital bone
& passes forward, to be attached to the aponeurosis.
 Each frontal belly arises from the aponeurosis & passes foreward, to
be attached to skin & superficial fascia of the eyebrow
Nerve Supply:
 Occipital belly is supplied by posterior auricular branch of facial
nerve; & Frontal belly by temporal branch of facial nerve.
Action:
 first three layers of scalp can be moved forward or backward,
 loose areolar tissue layer of the scalp allows the aponeurosis to move
on the pericranium.
 Frontal bellies raise eyebrows in expressions of surprise or horror.

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 Nerve Supply of Scalp
The main trunks of sensory nerves lie in
superficial fascia:
supratrochlear nerve, a branch of Ophthalmic
division of trigeminal nerve, supplies scalp as
far as the vertex of the skull.

supraorbital nerve, a branch of opthalmic

division of trigeminal nerve, supplies scalp, as
far backward as the vertex

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 Sensory Nerves of the Scalp
 zygomaticotemporal nerve, a branch of maxillary
division of trigeminal nerve, supplies scalp over the temple.
 auriculotemporal nerve, a branch of mandibular division
of trigeminal nerve,
  Its terminal branches supply skin over temporal region.

 lesser occipital nerve, a branch of cervical plexus (C2),

supplies scalp over lateral part of occipital region.
 - It also supplies skin over medial surface of the auricle.

 greater occipital nerve, a branch of posterior ramus of

2nd cervical nerve (C2), supplies skin as far forward as the
vertex of the skull.
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 Arterial Supply of Scalp
scalp has a very rich supply of blood
Thus, the smallest cut bleeds profusely.
The arteries lie in superficial fascia.
Moving laterally from the midline anteriorly, the
following arteries are present:

1. supratrochlear & 2. supraorbital

arteries, terminal branches of ophthalmic artery (a
branch of internal carotid artery), ascend over
forehead in company with supratrochlear &
supraorbital nerves.
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 Arterial Supply of Scalp
1. Supratrochlear a.:
Passes superiorly
from supratrochlear
notch
 Supplies muscles &
skin of scalp
2. Supraorbital a.:
Passes superiorly
from supraorbital
foramen
 Supplies muscles &
skin of forehead &
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scalp
 Arterial Supply of Scalp
3. superficial temporal a:
 smaller terminal branch
of external carotid
artery,
 ascends to scalp in front
of auricle in company
with auriculotemporal
nerve.
It divides into anterior &
posterior branches, which
supply Facial muscles &
skin over frontal &
temporal regions.
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 Arterial Supply of Scalp
Transverse facial
artery:
 Branch of superficial
temporal artery within
parotid gland
 Crosses face
superficial to
masseter muscle &
inferior to zygomatic
arch
 Supplies Parotid gland
& duct, muscles &
skin of face
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 Arterial Supply of Scalp

4. posterior auricular artery, a branch of external carotid

artery,
 ascends behind auricle & Passes posteriorly, deep to
parotid, along styloid process, b/n mastoid & ear
 Supplies Scalp posterior to & above auricle & the auricle

5. occipital artery, a branch of external carotid artery,

 ascends from apex of posterior triangle, in company with
greater occipital nerve.
 Passes medial to posterior belly of digastric & mastoid
process in occipital region

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 Venous Drainage of the Scalp
 supratrochlear & supraorbital veins unite at medial
margin of orbit to form the facial vein.
 superficial temporal vein unites with maxillary vein
in the substance of parotid gland to form
retromandibular vein.
 posterior auricular vein unites with posterior division
of the retromandibular vein, below parotid gland, to form
external jugular vein.
 Occipital vein drains into suboccipital venous plexus; 
the plexus in turn drains into vertebral veins.
 Occasionally, occipital vein drains forward into internal
jugular vein.
 veins of the scalp freely anastomose with one another &
are connected to diploic veins of skull bones & intracranial
80 venous sinuses by the valveless emissary veins
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 MENINGES: brain & spinal cord surrounded by three
layers of membranes (meninges)
 a tough, outer layer (dura mater),
 a delicate, middle layer (arachnoid mater),
 an inner layer firmly attached to surface of brain (the
pia mater).
 pia is inseparable from surface of brain.
 arachnoid is in touch with meningeal layer of dura & is
connected to the pia by many connective trabeculae.
 space b/n pia & arachnoid is subarachnoid space
 This space contains cerebrospinal fluid (CSF) .

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 cranial dura mater: a thick, tough, outer covering of the
brain.
 consists of an outer periosteal layer & an inner meningeal
layer:
 outer periosteal layer is firmly attached to the skull,
(periosteum of cranial cavity)
 inner meningeal layer is in close contact with arachnoid
mater & is continuous with spinal dura mater thru
foramen magnum.
 The two layers separate from each other at numerous
locations to form:
1. Dural partitions (Dural Septa), which project inward &
separate parts of brain;
2. Dural Venous Sinuses (intracranial venous structures).

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Dural partitions (Dural Septa):

 double layers of dura formed when the

meningeal layer of dura pulls away forming
dural septa
 project into cranial cavity & partially

subdivide cranial cavity.

 Include:
1.falx cerebri
2.falx cerebelli
3. tentorium Cerebelli
4. diaphragma sellae.
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falx cerebri:
 crescent-shaped

 projects downward b/n the two cerebral hemispheres.

tentorium cerebelli:
 a horizontal projection that covers & separates

cerebellum from posterior parts of cerebrum.

falx cerebelli:
 a small midline projection b/n the two cerebellar

hemispheres.
diaphragma sellae:
 covers the hypophysial fossa in the sella turcica of

sphenoid bone.

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 venous channels; drain blood from brain,
meninges and skull
 wall formed by dura and internal periosteum
 usually found along attachment of Dural septa
 Superior sagittal sinus
◦ along attached border of falx cerebri
◦ ends by turning to right transverse sinus (usually) or
dilate at termination and join the straight sinus,
together form the confluence of the sinuses
 Inferior sagittal sinus
◦ along free edge of falx cerebri
◦ ends joining great cerebral vein to form straight
sinus
87
 Straight sinus
◦ lies along junction of falx cerebri and tentorium
◦ ends by continuing as left transverse sinus (usually)
 Transverse sinuses
◦ along attached margin of tentorium
◦ ends bending downwards to become sigmoid sinus
 Sigmoid sinuses
◦ s-shaped
◦ at jugular foramen it becomes superior bulb of
internal jugular vein

88
 Occipital sinus
◦ lies in attached margin of falx cerebelli
◦ begins near foramen magnum and ends in
confluence of sinuses
 Sphenoparietal sinuses
◦ lies along posterior margin of lesser wing of
sphenoid
◦ drain into anterior part of cavernous sinus
 Superior petrosal sinuses
◦ lie in anterior part of attached margin of tentorium
◦ drain cavernous sinus to transverse sinus

89
 Inferior petrosal sinuses
◦ lie in petro-occipital fissure
◦ drain cavernous sinus into internal jugular vein
 Basilar sinus (plexus of veins)
◦ venous plexus on clivus
◦ connect the two inferior petrosal sinuses
 Intercavernous sinuses
◦ connects cavernous sinuses
◦ pass through diaphragma sellae

90
91
◦ Cavernous sinuses
◦ lie on each side of body of sphenoid, from superior
orbital fissure to apex of petrous temporal bone
◦ structures in lateral wall (from superior to
inferior)
 oculomotor nerve, trochlear nerve,
ophthalmic nerve, maxillary nerve,
trigeminal ganglion
◦ structures passing through the sinus
 internal carotid artery
 abducent nerve

92
 Tributaries
◦ from orbit – superior and inferior ophthalmic veins,
central vein of retina
◦ from brain – superficial middle cerebral and inferior
cerebral veins
◦ from meninges – sphenoparietal sinus, anterior trunk
of middle meningeal vein
 Communications
◦ transverse sinus through superior petrosal sinus
◦ internal jugular vein through inferior petrosal sinus
◦ pterygoid plexus through emissary veins
◦ facial vein through ophthalmic veins
◦ NB: All communications are valve less. Thus blood can
flow in any direction

93
94
95
Arterial supply of dura mater:
1. anterior meningeal arteries (branches of
ethmoidal arteries), in anterior cranial fossa;
2. middle (a branch of maxillary artery) &
accessory meningeal arteries, in middle
cranial fossa;
3. posterior meningeal artery (terminal branch
of ascending pharyngeal artery branch of
Maxillary Artery & other meningeal branches
in the posterior cranial fossa.

96
97
98
 Innervation: small meningeal branches of all 3
divisions of trigeminal nerve [V1, V2 & V3] & C1, C2 &
(C3).
 In Anterior cranial fossa  V1  meningeal branches
from ethmoidal nerves, supply floor & anterior part
of falx cerebri.
 V1 also turns & runs posteriorly, supplying tentorium
cerebelli & posterior part of falx cerebri.
 Middle cranial fossa  supplied medially by maxillary
nerve [V2] & laterally, by mandibular nerve [V3].
 Posterior cranial fossa is supplied by branches from
C1, C2 & C3 cervical nerves & by meningeal branches
of vagus n.
99
 The three meningeal spaces include:
 extradural (epidural) space b/n cranial bones & dura:

 is a potential space normally (becomes a real space

pathologically: eg. if blood accumulates in it);
 subdural space is a potential space b/n dura & arachnoid;

 subarachnoid space is the normal space b/n arachnoid &

pia, which contains cerebrospinal fluid (CSF).

 Extradural (epidural) hematomas: result from bleeding

from a torn middle meningeal artery.

 Subdural hematomas: commonly result from tearing of a

cerebral vein (usually, superior cerebral vein) as it enters

superior sagittal sinus.
 Subarachnoid hemorrhage: results from bleeding within

subarachnoid space, e.g., from rupture of an aneurysm.

 The dura is sensitive to pain

 distention of scalp or meningeal vessels (or both)

may be one cause of headache.

Many headaches appear to be dural in origin:

These headaches may result from stimulation of
sensory nerve endings in the dura.

10
1
 A hard blow to side of the head may fracture thin
bones forming the pterion, rupturing anterior
branch of middle meningeal artery crossing the
pterion.
 The resulting extradural (epidural) hematoma

exerts pressure on underlying cerebral cortex.

 Untreated middle meningeal artery hemorrhage

may cause death in a few hours.

10
2
 Venous Drainage of the Scalp

103
 The Face

Boundaries
 Superiorly – the margins of the hair
 Inferiorly – the chin
 Laterally – the auricle
N.B. the forehead is common for the scalp and the face
104
Skin
Very vascular; wounds bleed profusely but heal
rapidly
Rich in sebaceous and sweat glands
Lax except in ear and nose; edema spread rapidly
Elastic and thick; wounds tend to gap
Superficial fascia
Contain facial muscles, nerves, vessels and fat (buccal
fat pad in cheeks)
Deep fascia
Absent except over parotid gland and over buccinator
muscle
105
 Muscles of the face
Lie in subcutaneous tissue
Inserted in to the skin
Named as muscles of facial expression
Arranged in groups around the orbit, nose, mouth
and auricles
functionally considered as regulators of
openings
Supplied from branches of facial nerve

106
Muscles of the eyelids and eyebrow
Orbicularis Oculi
Three parts - supplied by temporal branches of
facial nerves
1. Palpebral
 Origin: Medial palpebral ligament and bones
above and below the ligament
 Insertion: Skin of the eye lid passing anterior to
the tarsal plate
 Action: Close the palpebral fissure firmly to
protect from danger

107
 2. Orbital
 Origin: Medial palpebral ligament and bones above and
below the ligament
 Insertion: No lateral attachment b/c the fibers form
concentric ring
 Action: Gentle close, during sleeping
3. Lacrimal
 Origin: Two- posterior margin of the fossa of
lacrimal sac and sheath of the lacrimal sac
 Insertion: upper and lower eyelids, upper and lower
tarsi
 Action: Passing tear into lacrimal puncta by drawing
the eye- lids medially, dilating the lacrimal fossa
108
109
 2. Corrugators supercilli
Origin: Medial part of superciliary arch
Insertion: Skin of eye brows
Action: Vertical wrinkling of middle part of fore
head (frowning)
N.S. Temporal branch of facial nerve
Levator palpebrae superioris
Raises upper eye lid

110
 Muscles around nose

Muscle Origin Insertion Action

Transverse
Nasal bone & Medial part
Proceruss wrinkles
lateral of the skin of
(horror)
cartilage the eye brows

Maxilla Join the fibers Compress

Compressor
(frontal of its opposite anterior nasal
naris
process) side opening

111
Dilator naris Maxilla Ala of nose

Depressor septi Maxilla (above Nasal septum Dilates anterior

central incisor)  nasal openings

Levator labii Maxilla (frontal Cartilage and Dilates anterior

superioris process) skin of ala of nasal openings
alaeque nasi anterior nasal Elevate the
opening upper lip
Skin of upper lip
Nerve supply – buccal branch

112
 Muscles around mouth
Levator labii Cartilage and skin of Skin of
superioris ala of anterior nasal upper lip
alaeque nasi opening

Muscles
Levator labi Maxilla and
elevating the
superioris zygomatic bone
upper lip
Zygomaticus Behind
minor zygomaticomaxillary
suture

113 Nerve supply – buccal branch of facial nerve

 Muscles Zygomaticus Zygomatic Skin angle
elevating major bone of the
the angle of behind mouth
the mouth zygomatic Buccal
minor branch
Levator Maxilla
anguli oris below
infraorbital
foramen

Muscles Depressor Oblique Skin angle

depressing anguli oris line of of the Mandibular
the angle of mandible mouth branch
the mouth

114
Muscle pulling Risorius Parotid Skin of Buccal
the angle of fascia angle of branch
mouth laterally the mouth
Muscles Depressor Oblique line Angle of Mandibular
depressing the labi of mandible the mouth branch
lower lip inferioris Skin of
lower lip
Muscles Incisor fossa Skin of the Mandibular
protruding the of the chin branch
lower lip and Mentalis mandible
wrinkling the
skin of the chin

115
 Buccinator
 Origin: Two site
 Pterogomandibular ligament
 Maxilla and mandible (opposite 3rd molar tooth)
 Insertion:
 Upper fibers – upper lip
 Middle – decussate at the angle
 Lower- lower lip

Nerve supply: Buccal branches of facial nerve


 Action: Compress the cheek against the gum
 prevent accumulation of food in the vestibule
 Superficial to the buccinator muscle there is buccopharyngeal
fascia, structures piercing are
 Parotid duct – opposite the 2nd upper molar
 Buccal branches of facial nerve- supply the mucus of the cheek

116
Orbicularis Oris
Three parts
Origin:
Intrinsic fibers – connect the skin and mucus membrane
Incisive bundles- maxilla and mandible
Extrinsic fibers – surrounds the mouth
Insertion: No attachment because the fibers form
concentric ring
Nerve supply: Buccal and mandibular branches of facial
nerves
Action:
Close the oral fissure
Compress the lips against the teeth
protrude the mouth
117
118
 Muscles the auricle
Rudimentary in human
Anterior auricular
Posterior auricular
Superior auricular
All are not functional in humans and supplied by
branches of facial nerve

119
 Muscles of facial expressions

120
 Sensory Nerves of the face

 Two sources
 Skin around the angle of the mandible – greater
auricular nerve (C 2, 3 )
 The rest of the face- trigeminal branches

121
 Sensory Nerves of the Face
1. Ophthalmic division:
supplies skin over top of
head, forehead, upper
eyelid, conjunctiva & a
portion of the nose:
(roughly corresponds to
upper 1/3 of face & head.

2. Maxillary division: supplies

skin, over lower eyelid,
portion of nose, upper part
of the cheek & upper lip:
(corresponds to the area in
relation to upper jaw.
3. Mandibular branch supplies
skin over the lower jaw.

122
123
124
125
 Trigeminal nerve (CN V)
Sensory to face and motor to muscles of mastication
3 branches
Ophthalmic nerve
Sensory
three branches; lacrimal, frontal and nasociliary
Lacrimal – supply lacrimal gland and conjunctiva and lateral part
of the upper eyelid
Frontal – 2 branches
Supraorbital –lateral forehead and front of scalp
Supratrochlear – supply middle forehead
Nasociliary
Infratrochlear – skin and conjunctiva of the medial part of the
eyelid, skin of the upper ½ of the nose
External nasal - skin of the lower ½ of the nose

126
Maxillary nerve
Three cutaneous branches
1. Infraorbital – terminal branch; three branches
1.Palpebral – skin and conjunctiva of the lower eye lid
2.Nasal – skin of the side of the nose
3.Labial – skin and mucus membrane of the upper lip
2. Zygomaticotemporal - skin over the anterior ½ of the
temple and the scalp
3. Zygomaticofacial - skin over the zygomatic bone

127
  Mandibular nerve
4 sensory branches
1. Auriculotemporal - posterior 1/2 of the temple,
upper 2/3 of the lateral surface of the auricle & skin
of the external acoustic meatus, ear drum
2. Buccal - skin and mucus lining of the cheeks
3. Inferior alveolar – lower teeth
1.incisive nerve – incisor and gingiva
2.Mental nerve – skin and mucus lining of the
lower lip and chin
4. Lingual – general sensory to anterior 2/3 of tongue

128
129
 Facial nerve (CN VII)
Supply
Motor to muscles of facial expression
Sensory to taste buds in anterior 2/3 of tongue
Secretomotor to submandibular and sublingual glands
Emerge through stylomastoid foramen and enter
parotid and gives five branches
Temporal – supplies orbital and forehead muscles
Zygomatic – supplies muscles in zygomatic, orbital
and infraorbital region
Buccal – supplies buccinator and muscles in upper lip
Mandibular – supplies muscles in lower lip and chin
Cervical – supplies platysma
130
131
 Clinical correlations

Bell's palsy
Lesions of the facial nerve
Results in dribbling of tears and saliva due to
paralysis of the orbicularis muscles; and
paralysis of buccinators lead to accumulation
of food in the vestibule
Test by asking patients to smile or to whistle
loss of muscle tone causes the normal skin folds to
disappear on the side of the lesion
132
  Clinically four muscles are important in
evaluating the integrity of the facial nerve.
These are:

1.Frontalis muscle- which raises the eyebrows.

2.Orbicularis oculi muscle – enables closing of
eyelids
3.Orbicularis oris muscle – ability to smile.
4. Buccinator muscle – ability to whistle or
to suck.

133
 The Facial Nerve

134
 Blood vessels of the face
Arteries
 six arteries which have free anastomosis
1. From ophthalmic artery - two arteries originating in the
orbit
 Supratrochlear
 Supraorbital
2. From external carotid artery – four arteries
 external carotid artery in the parotid gland divides in to
two terminal branches: maxillary and superficial
temporal arteries

135
 A. Facial artery
 Origin - arise from external carotid artery in
the neck, major blood supply of the face
 Course
 tortuous course
 run to lower border of mandible, at the anterior
border of the masseter the pulse is felt
 then ascends first to the angle of the mouth and
then up at the side of the nose to the medial angle
of the eye
 The main branches
 Superior labial – upper lip
 Inferior labial – lower lip
 Lateral nasal – nose
136
 B. Transverse facial
 a branch of superficial temporal artery
 enters the face at the anterior upper border
of the gland
 distribution- the face, parotid gland and its
ducts
C. Infraorbital – one of the terminal branch of
maxillary artery
D. Mental artery- from inferior alveolar artery

137
138
139
140
 Veins
 Free anastomosis
1. Supratrochlear veins
1. Begins on forehead; descends near middle and joins
supraorbital vein near orbit to form facial vein
2. Supraorbital veins
1. begins near zygomatic process; descends medially and
join supratrochlear
3. Facial vein
1. formed by union of supratrochlear and supraorbital veins
at the medial angle of the orbit
2. Course - leave the face at the anteroinferior angle of
masseter; pierce the deep fascia of the neck; crosses the
submandibular gland; join the anterior division of
retromandibular vein to form the common facial vein
draining into the internal jugular vein
3. Tributaries - veins accompanying facial artery
141
  facial vein communicates with
 Pterygoid venous plexus through deep facial vein
 Cavernous sinuses through ophthalmic veins
 Blood normally drain from angle of eye, nose and lips
inferiorly but it may run in opposite direction and enter
cavernous sinus
 This area (nose, medial angle of eye and the upper lip)
form danger area of the face
4. Superficial temporal
 drain forehead and scalp
5. Retromandibular vein
 formed by union of superficial temporal and maxillary
veins
 descend within parotid gland and at end divide into
anterior and posterior divisions
142
143
144
 Clinical Conditions

The superficial temporal artery & facial artery are

commonly used by the anesthetist to take the patient's pulse.
The area of facial skin bounded by the nose, the eye, and
the upper lid is a potentially dangerous zone to have an
infection:
 For example, a boil in this region may cause thrombosis of
the facial vein, with spread of organisms thru the superior
& inferior ophthalmic veins to the cavernous sinus.
The resulting cavernous sinus thrombosis may be fatal
unless adequately treated with antibiotics.

145
 fig. Potentially dangerous zone or triangle the face
146
 Lymphatic drainage
 3 territories
 upper territory - lateral forehead, lateral half of
eyelid and face drain into parotid lymph nodes
 middle territory - median forehead, nose, upper
lip, lateral part of lower lip, medial part of eyelid
and cheeks, most of lower jaw drain into
submandibular lymph nodes
 lower territory - median part of the lower lip and
chin drain into submental lymph nodes

147
148
 The Parotid Region

Space between mastoid process and neck

and ramus of mandible

149
 Contents
The parotid gland – the largest salivary gland
Facial nerve and its branches (5)
Facial vein
External carotid artery and its branches
Lymph nodes

150
 The parotid gland
Location
Parotid bed – space between mastoid process
and ramus
Anteriorly – ramus of the mandible
Posteriorly- mastoid process and sternocleidomastoid
muscle
Superiorly – external acoustic meatus
Inferiorly – little below the angle of the mandible
Shape - pyramid; apex – downwards
Feature – irregularly lobulated
151
 Surfaces – four
Lateral (superficial)
Anteromedial
Posteromedial
Superior
Borders
three – Anterior, Posterior & Medial

152
 Relations
Apex – over posterior belly of digastric muscle and
carotid triangle
Superior surface - external acoustic meatus, TMJ,
superficial temporal vessels and auriculotemporal
nerve
Laterally (superficial surface) – skin, superficial
fascia containing platysma and great auricular
nerve, deep fascia (parotid capsule) and parotid
lymph nodes
Posteromedial surface - mastoid process, posterior
auricular artery and occipital artery, styloid process
and attached muscles, carotid sheath, terminal
braches of external carotid artery
Anteromedial surface – ramus border, masseter
muscle, TMJ, medial pterygoid muscle
153
154
 Structures with in the gland: superficial to deep
Facial nerve and its branches
Retromandibular vein
External carotid artery and its braches

155
 Facial nerve
Emerges from stylomastoid foramen
Enter the gland at posteromedial surface
Divide into 5 branches: temporal, zygomatic,
buccal, mandibular and cervical
Leave through anteromedial surface

156
157
158
 Retromandibular vein
Formed by union of superficial temporal and maxillary veins
Divide at apex into anterior and posterior divisions
Anterior joins facial vein to form common facial vein
Posterior joins posterior auricular vein to form external
jugular vein

External carotid artery

Enters through posteromedial surface
Divide into superficial temporal and maxillary arteries

159
160
 Capsule of the parotid gland
Derived form deep fascia of the neck
Firmly attached with the gland and its deep
part is thickened to form stylomandibular
ligament which separate the parotid gland
from submandibular salivary gland

161
 The parotid duct
5 cm long
Origin - from the anterior border of the gland; Superficial to
the masseter, below the transverse facial artery
Course - runs forward on masseter and turn medially at
masseter border and pierce buccal fat pad, buccopharyngeal
fascia, buccinator muscle and mucus membrane consecutively
Open to - vestibule of the mouth opposite to the 2nd

maxillary molar teeth

162
Blood supply
Arteries - branches of external carotid
Veins – drains into retromandibular vein
Nerve supply
Parasympathetic – secretomotor
 Reach through Auriclotemporal nerve
 Inferior salivary nucleus → Glossopharyngeal n → tympanic branch →
tympanic plexus → lesser petrosal nerve → otic ganglion →
auriclotemporal nerve → parotid gland
Sympathetic - vasomotor
 form cervical ganglion through sympathetic plexus around the external
carotid artery
Sensory
 From auriculotemporal nerve
 Parotid fascia - great auricular

163
 Lymphatic drainage
Superficial and deep parotid → superficial and deep cervical
nodes
Applied anatomy
Parotid fascia is adherent to the gland firmly which limit
swelling, thus parotid infection is painful

164
 Parotid Gland
A malignant tumour of parotid gland, unlike benign
lesions, may involve VII and produce a facial palsy.
During parotidectomy, identification, dissection, and
preservation of branches of facial nerve are critical.
parotid gland may be infected by infectious agents that
pass thru the bloodstream, as in mumps, an acute
communicable viral disease.
Infection of the gland causes inflammation (parotiditis)
& swelling of the gland.
Severe pain occurs because the parotid sheath,
innervated by great auricular nerve, limits the swelling.
165
 The parotid gland
Because the pain produced by mumps may be
confused with a toothache:  redness of the papilla
(opening of the parotid duct) is often an early sign that
the disease involves the gland and not a tooth.

Parotid gland disease often causes Referred Pain in

the auricle, external acoustic meatus, temporal
region & temporomandibular joint (TMJ) because
the auriculotemporal nerve, sensory nerve of parotid
gland, also supplies sensory fibers to the skin over the
temporal fossa and auricle.
 The temporal and infratemporal
region

167
 Temporal fossa
 Boundary
 Superior and posterior – temporal lines
 Anterior – frontal and zygomatic bones
 Temporal fascia – stretch over it
 Floor – formed by parietal, frontal, greater wing of
sphenoid and squamous temporal bone
 Contents – Temporalis muscles
 Fan shaped
 Origin – temporal fossa and fascia
 Insertion – coronoid process and anterior border of ramus
 Nerve supply – mandibular nerve
 Action – elevate and retract mandible

168
 The infratemporal fossa
Inferior and deep to zygomatic
arch and posterior to maxilla
Boundaries
Anterior wall - posterior surface
of maxilla
Medial wall - lateral pterygoid
plate
lateral wall – ramus of mandible
posterior wall - condylar process
of mandible and styloid process
Roof - greater wing of sphenoid
Inferior boundary – attachment
of medial pterygoid muscle to
mandible
169
 Communications
superolaterally - temporal fossa through gap between
zygomatic arch and skull
Medially - pterygopalatine fossa
Anteriorly - orbital cavity through the inferior orbital fissure
Superiorly - middle cranial fossa through the foramen
spinosum and ovale
Pterygomaxillary fissure - between posterior surface of
maxilla and the upper part of lateral pterygoid; for the
passage of the maxillary artery and nerve

170
 Contents
Superficial
 Lateral Pterygoid muscle
 Medial Pterygoid muscle
 Temporomandibular joint
 Maxillary artery and vein
 Pterygoid plexus
Deep
 Mandibular nerve and its branches
 Chorda tympani nerve
 Otic ganglion
 Part of the maxillary nerve
 Tensor palatini

171
172
173
174
175
176
 Maxillary artery
larger terminal branch of external carotid artery
Course – lateral pterygoid muscle divide it into three parts
The first part – mandibular part
 Neck of mandible to lower border of the lateral pterygoid muscle
 Relations
 Lateral – mandible (neck)
 Medial – Sphenomandibular ligament
 Superior – auriculotemporal nerve

177
 Branches
Middle meningeal - deep to the lateral pterygoid, between the
2 roots of the auriculotemporal nerve, enter cranial cavity
through foramen spinosum
Accessory meningeal – in front of middle meningeal, deep to
lateral pterygoid, enter cranial cavity through foramen ovale
Deep auricular – to external acoustic meatus, tympanic
membrane and TMJ
Anterior tympanic – middle ear and tympanic membrane
Inferior alveolar – gives off lingual and mylohyoid branches;
then enter mandibular canal through mandibular foramen;
within the canal gives off alveolar branches to lower jaw
teeth and exit through mental foramen to supply chin

178
 The second part – Pterygoid part
superficial or deep to lateral pterygoid muscle
Branches – muscular to muscles of mastication and buccinator
Third part – Pterygopalatine part
Passes medially between the two heads of the lateral
pterygoid muscle; pass through pterygomaxillary
fissure into pterygopalatine fossa
Branches
Posterior superior alveolar – upper molar and premolar teeth
and maxillary sinus
Infraorbital – enter orbit through inferior orbital fissure, run
forward in floor of orbit and emerge on face through
infraorbital foramen
o branches : orbital, anterior superior alveolar – Upper canine & incisor
179
 Greater palatine – runs downward and emerge on
posterolateral part of hard palate; then runs
forward and enter incisive canal
o Supply palate and gums
o gives the lesser palatine branch for soft palate
and tonsil
Sphenopalatine – supply nasal cavity
Pharyngeal – supply nasopharynx, auditory tube
and sphenoidal sinus
Artery of the pterygoid canal – supply pharynx,
auditory tube and tympanic cavity

180
 Infratemporal Fossa: Maxillary artery
•The maxillary artery arises at
the neck of the mandible & is
divided into three parts by the
lateral pterygoid m: it can
pass medial or lateral to the
lateral pterygoid:
1.the first or retromandibular
part
2.second or pterygoid part
(directly related to the lateral
pterygoid)
3.the third (pterygopalatine)
part
 Infratemporal Fossa: Maxillary artery

•branches of the first part

(pass thru foramina or
canals):
1. deep auricular to external
acoustic meatus,
2. anterior tympanic to the
tympanic cavity,
3. middle & 4. accessory
meningeal to the cranial
cavity, & 5. inferior alveolar
to the mandible & teeth.
 Infratemporal Fossa: Maxillary artery
• branches of the second part
supply muscles via the:
1.masseteric, 2. deep temporal,
3. pterygoid, & 4. buccal
branches.
• branches of the third part:
1. posterior superior alveolar,
2. descending palatine,
3. infraorbital,
4. Pharyngeal thru palatovaginal
canal to supply mucosa of nasal
roof
5. Artery of pterygoid canal thru
pterygoid canal; supplies mucosa
of upper pharynx &
6. sphenopalatine arteries arise
within the pterygopalatine fossa.
184
 Pterygoid plexus of veins
Surrounds the lateral pterygoid muscle
Receive tributaries of the corresponding branches of the
maxillary artery
The plexus posteriorly unite to form the maxillary vein
Communications
 Inferior ophthalmic vein
 Cavernous sinus – through emissary veins passing through foramen
ovale and spinosum
 Facial vein – through inferior ophthalmic vein & deep facial vein

185
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Mandibular nerve
Course
Two roots – larger sensory and smaller motor
Reach the infratemporal fossa through foramen
ovale and below the foramen the two roots unite
Divisions
anterior - motor only
posterior - mainly sensory
Relations
Medial – tensor palatini and otic ganglion
Laterally – lateral pterygoid muscle
Posteriorly – middle meningeal artery

187
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189
 Branches
From the trunk
Meningeal branch – enter skull through foramen
spinosum; supply dura in middle cranial fossa
Nerve to the medial pterygoid – supply medial
pterygoid, tensor palati and tensor tympani and
send fiber to the otic ganglion
From the anterior division
buccal – skin and mucosa over buccinator
masseteric – masseter and TMJ
nerve to lateral pterygoid
deep temporal nerve – for temporalis muscle
190
 From the posterior division
Auriculotemporal nerve
Arise by two roots, surround the middle meningeal
artery
Carry postganglionic parasympathetic fiber from otic
ganglion to the parotid gland
Branches supply
o TMJ
o Auricle
o external acoustic meatus
o tympanic membrane
o temple with the scalp
o Parotid gland

191
 Lingual nerve
Arise deep to the lateral pterygoid, joined by chorda
tympani (a branch of facial nerve) in the infratemporal fossa
Enter mouth between medial pterygoid and ramus and pass
anteriorly under oral mucosa
Run over hyoglossus and genioglossus and divide to supply
tongue

192
Inferior alveolar nerve
deep to the lateral pterygoid muscle
accompanied by the inferior alveolar vessels
enters the mandibular foramen and run through
mandibular canal and appear on face as mental nerve
Branches
Before entry to mandibular foramen
Nerve to mylohyoid muscle – supply mylohyoid
and anterior belly of digastric
In the mandibular canal
Branches to lower teeth
Terminal
Mental nerve – supplies chin, lower lip and gingiva
193
194
195
 Chorda tympani
Originate from facial nerve behind the middle ear cavity →
petrotympanic fissure → infratemporal fossa → lingual
nerve
Contains two types of fiber
Preganglionic parasympathetic secretomotor fibers to the
submandibular and sublingual salivary glands. The
postganglionic arise from the submandibular ganglion
Taste (special sense) from the taste buds of the anterior 2/3
of the tongue

196
197
 Otic ganglion
parasympathetic ganglion in infratemporal fossa,
just below the foramen ovale
Relations
Laterally – mandibular nerve
Medially – tensor tympani muscle
Posteriorly – middle meningeal artery

198
 Roots
Parasympathetic – derived from glossopharyngeal nerve
o Preganglionic fibers pass through tympanic branch and
plexus, and lesser petrosal nerve
o Postganglionic fibers pass through auriculotemporal nerve
Sympathetic – derived from plexus over the middle
meningeal artery
o Contain postganglionic fibers from superior cervical ganglion
o Do not relay
o Reach the gland via auriculotemporal nerve
o vasomotor
Sensory – from auriculotemporal nerve

199
 Branches
To auriculotemporal – the fibers contain
Parasympathetic to parotid salivary gland
Sympathetic - to the vessels of the parotid gland
Sensory – from the parotid gland

200
201
 Muscles of mastication
Move mandible at TMJ
All are supplied by mandibular nerve
Masseter
Origin – zygomatic arch
Insertion – ramus of mandible and coronoid process
Action – elevates mandible
Temporalis
Origin – temporal fossa and fascia
Insertion – coronoid process and ramus
Action – elevate and retract mandible

202
 Lateral Pterygoid
Origin – upper head (greater wing) and lower head (lateral
pterygoid plate)
Insertion – neck of mandible and capsule of TMJ
Action
 together – depress and protrude mandible
 Alone – side to side movement

Medial pterygoid
Origin – superficial head (maxilla) and Deep head (lateral
pterygoid plate and palatine bone)
Insertion – ramus
Action
 together – elevates and protrude mandible
 Alone - produce grinding motion

203
 Muscles of Mastication

204
 Muscles of Mastication

205
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207
208
209
 Pterygopalatine Fossa
The pterygopalatine fossa is an inverted 'tear-drop'
shaped space b/n lateral pterygoid plate (posteriorly) &
posterior to the maxilla (anteriorly)
Strategically located, the pterygopalatine fossa
communicates via fissures and foramina in its walls with:
1. the middle cranial fossa;
2. infratemporal fossa;
3. floor of the orbit;
4. lateral wall of the nasal cavity;
5. nasopharynx;
6. roof of the oral cavity.
210
 Pterygopalatine Fossa

211
 Pterygopalatine Fossa

The pterygopalatine fossa communicates:

Laterally with the infratemporal fossa, thru the
pterygomaxillary fissure.
Medially with the nasal cavity thru sphenopalatine
foramen.
Anterosuperiorly with the orbit thru the inferior orbital
fissure.
Posterosuperiorly with the middle cranial fossa thru
foramen rotundum & pterygoid canal.

212
 Pterygopalatine Fossa
 the pterygopalatine fossa is a major site of distribution for the
maxillary nerve [V2] & for terminal part of maxillary artery.
 In addition, parasympathetic fibers from the facial nerve [VII]
and sympathetic fibers from T1 spinal cord (superior cervical
ganglia) join branches of maxillary nerve [V2] in the
pterygopalatine fossa.
 The pterygopalatine ganglion, which contains cell bodies for the
postganglionic parasympathetic fibers in the greater petrosal
branch of facial nerve [VII], is formed in the fossa.
 All the upper teeth receive their innervation and blood supply
from the maxillary nerve [V2] and the terminal part of the
maxillary artery, respectively, that pass thru pterygopalatine fossa.

213
 Pterygopalatine Fossa: Communications
 Seven foramina and fissures provide apertures thru which
structures enter & leave the pterygopalatine fossa:
1. foramen rotundum & pterygoid canal communicate with the
middle cranial fossa;
2. a small palatovaginal canal leads to the nasopharynx;
3. palatine canal leads to roof of oral cavity (hard palate);
4. sphenopalatine foramen opens onto the lateral wall of the nasal
cavity;
5. lateral aspect of the pterygopalatine fossa is continuous with the
infratemporal fossa via a large gap (pterygomaxillary- fissure);
6. inferior orbital fissure opens into the floor of the orbit.

214
 Pterygopalatine Fossa: Communications

215
 Pterygopalatine Fossa: Communications

216
 Pterygopalatine Fossa: Contents
Contents of the Pterygopalatine Fossa:
1. The maxillary nerve [V2] & terminal part (3rd part) of the maxillary
artery.
2. Nerve of the pterygoid canal enters the fossa carrying:
 preganglionic parasympathetic fibers from greater petrosal branch of the
facial nerve [VII];
 postganglionic sympathetic fibers from the deep petrosal branch of the
internal carotid plexus of superior cervical ganglia.
3. the pterygopalatine ganglion;  parasympathetic fibers synapse here,
but sympathetic fibers do not synapse here.
 Both sympathetic & postganglionic parasympathetic fibers pass with
branches of maxillary nerve [V2] out of the fossa.
4. arteries, veins & lymphatics also pass thru the pterygopalatine fossa.

217
 Pterygopalatine fossa: Nerves

218
 Pterygopalatine fossa: Vessels & nerves
 The pterygopalatine (3rd) part of the maxillary artery, passes thru the
pterygomaxillary fissure & enters the pterygopalatine fossa.
 branches of the third, or pterygopalatine, part of maxillary artery are :
1. Posterior superior alveolar artery.
2. Descending palatine artery, divides into greater & lesser palatine aa.
3. Artery of the pterygoid canal.
4. Sphenopalatine artery, which divides into posterior lateral nasal
branches to the lateral wall of the nasal cavity & its associated paranasal
sinuses, and the posterior septal branches.
5. Infraorbital artery, which gives rise to the anterior superior alveolar
artery and terminates as branches to the inferior eyelid, nose, and upper
lip.

219
 Pterygopalatine fossa: Vessels & nerves

220
 Pterygopalatine fossa: Vessels & nerves
Posterior view

Sphenoid
sinus

Pterygopalatine
ganglia
Nasopalatine
nerve Post. Sup. Alveolar
a&n
Sphenopalatine Post sup lat nasal a & n
artery
Descending palatine a & n
Nasal cavity
Post inf lat nasal a & n
Nasal septun
Greater & lesser
palatine a & n

Lesser palatine a & n

Hard palate greater palatine
a&n
221