RUNGTA COLLEGE OF DENTAL SCIENCES & RESEARCH,BHILAI

DEPARTMENT OF Pedodontics and

preventive dentistry

PRESENTER:
DR.SANHATI
BISWAS
1ST YEAR PG
TRIANGLES OF NECK
 CONTENTS
1.INTRODUCTION
2.BOUNDARIES OF NECK
3.FASCIAL COMPARTMENTS OF NECK
4.TRIANGLES OF NECK
5.MUSCLES OF NECK
6.BLOOD & NERVOUS SUPPLY
7.LYMPH NODES
8.REFERENCES
 INTRODUCTION

• The neck is the part of

the body that separates
the head from the
torso.
• Antero-laterally, the
neck appears as
Quadrilateral in shape.
• LIMITATIONS:

• Superiorly - base of the

mandible and a line continued
from the angle of the
mandible to the mastoid
process.

• Inferiorly - upper border of

the clavicle.

• Anteriorly - anterior median

line.

• Posteriorly - anterior margin

of trapezius.
• Superficial structures from the lateral view
of the neck.

• Sternocleidomastoid
• Trapezius
• Occipital lymph nodes (on)
• Retro auricular lymph nodes (ran)
• Superficial cervical lymph nodes (scn)
• Sub mental lymph nodes (smn)
• Buccal lymph nodes (bn)
• Parotid lymph nodes (pn)
• Submandibular lymph nodes
 LAYERS OF THE NECK

1. SKIN
2. SUPERFICIAL FASCIA
3.DEEP CERVICAL FASCIA
 SKIN

• It is the outermost covering of neck.

• Anteriorly-Loosely attached.
• Posteriorly- it is very thick and adherent to underlying
structures with numerous sebaceous glands.
• It is well supplied with blood vessels and it has transverse
adherent lines.
 SUPERFICIAL CERVICAL FASCIA
• It is a thin lamina
covering Platysma.

• The superficial
cervical fascia is zone
of loose connective
tissue between
the dermis and
the deep cervical
fascia .
• CONTENTS:

Cervical branch of facial nerve

Superficial veins (e.g. anterior jugular vein)
Superficial lymph nodes
Fat
Platysma muscle
In obese individuals, extra fat is deposited in the superficial fascia, creating
the ‘double chin’.
DEEP CERVICAL FASCIA
1. ANTERIOR LAYER
• Investing Fascia
• Parotidomassetric Fascia
• Temporal Fascia

2. MIDDLE LAYER
• Sternohyoid-Omohyoid Division
• Sternothyroid-Thyrohyoid Division
• Visceral Division
a) Buccopharyngeal
b) Pretracheal
c) Retropharyngeal

3 POSTERIOR LAYER
• Alar Division
• Prevertebral
 FASCIAL COMPARTMENTS OF NECK

The fascia of the neck has a

number of unique features.

•The superficial fascia in the neck contains

a thin sheet of muscle (the PLATYSMA)

•PLATYSMA begins in the superficial

fascia of the thorax.

•It runs upwards to attach to the mandible.

•And blends with the muscles on the face.
The arrangement of the various layers of
cervical fascia organizes the neck into four
longitudinal compartments:

1. FIRST COMPARTMENT:
-largest
-includes the other three

2. VERTEBRAL COMPARTMENT:-
-vertebral column
-deep muscles associated with this
structure
-area contained within the
prevertebral layer
3.VISCERAL COMPARTMENT-
Parts of the respiratory &
digestive tract,
-pharynx
-trachea
-esophagus
-thyroid gland

4. VASCULAR COMPARTMENTS-
-major blood vessels
-vagus nerve.
 CAROTID SHEATH
•The carotid sheath consists of the
neurovascular structures that pass from
the base of the skull to the thoracic
cavity, and the sheath enclosing these
structures receives contributions from
the other cervical fascias.

CONTENTS:

1. INTERNAL CAROTID ARTERY

2. INTERNAL JUGULAR VEIN
3. VAGUS NERVE
TRIANGLES OF NECK

• The neck is arbitrarily

subdivided into two
triangles by the
sternocleidomastoid
muscle.

• 1. Anterior Triangle

• 2. Posterior Triangle
 ANTERIOR TRIANGLE OF NECK

Anteriorly- Median line of the

neck.

Posteriorly- Anterior margin of the

sternocleidomastoid muscle.

Base- Inferior border of the

mandible.

Apex- Manubrium Sterni

SUBDIVISIONS:
It is subdivided into:

a)Submandibular Triangle

b)Submental Triangle

c)Muscular Triangle

d)Carotid Triangle
 SUB MANDIBULAR TRIANGLE
• It is also called as the ‘Digastric
Triangle’.

• Boundaries:
• Above- by the lower body of the
mandible and the mastoid process.

• Posteroinferiorly- by the posterior

belly of digastric and the
stylohyoid.

• Anteroinferiorly- by the anterior

belly of digastric.

• Floor- Hyoid and Hyoglossus.

 CONTENTS
• Anterior Region:
• Submandibular Gland
• Facial Vein(superficial)
• Facial Artery(deep)
• Submental Artery
• Mylohyoid Artery & Nerve
• Submandibular Lymph Nodes

• Posterior Region:
• Lower Part Of Parotid Gland
• External Carotid Artery
• Internal Carotid Artery
• Jugular Vein
• Vagus Nerve
• Intermediate Tendon Of Digastric
And Stylohyoid
• Hypoglossal Nerve
 APPLIED ANATOMY OF
SUBMANIBULAR TRIANGLE
• Infection in Submandibular region is
limited to a triangular zone because the
layer of deep fascia is attached to these
bones,

• Posteriorly- to the Hyoid bone

• Anterolaterally-on each side by halves

of Mandibular base

• This triangular swelling is called as

LUDWIG’S ANGINA.

• The swelling may push tongue

upwards & posterior compromising the
airway.
 SUBMENTAL TRAINGLE
The single Submental triangle
is demarcated by the anterior
bellies of both digastric
muscles.

BOUNDARIES:

Apex is at the chin

Base is the body of the hyoid

bone

Floor is formed by the both

mylohyoid muscles

CONTENTS:
Lymph nodes and small veins
that unite to form the Anterior
jugular vein.
 MUSCULAR TRIANGLE

Boundaries:

• Anteriorly: Midline Of Neck

• Posterosuperiorly: Superior
Belly Of Omohyoid

• Inferoposteriorly: Anterior
Margin of
Sternocleidomastoid
CONTENTS:

THE INFRAHYOID MUSCLES

Superficial layer:

1. Sternohyoid: medially

2. Omohyoid: laterally

Deep layer:

3. Thyrohyoid: above
4. Sternothyroid: below
 CAROTID TRIANGLE
The carotid triangle is covered by the
• Skin
• Superficial fascia
• Platysma
• Deep fascia containing branches of the
fascial and cutaneous cervical nerves.
BOUNDARIES:
• Superiorly: Stylohyoid And Posterior
Belly Of Digastric
• Anteroinferiorly: Superior Belly Of
Omohyoid
• Posteriorly: Sternocleidomastoid
FLOOR:
• Anteriorly: Hyoglossus & Thyrohoid
Muscles
• Posteriorly: Middle & Inferior
Constrictors Of Pharynx
 CONTENTS OF CAROTID TRIANGLE
ARTERIES:
1. Termination of common carotid: at
level of disc between C3 & C4
(level of upper border of thyroid
cartilage)
2. Proximal part of External Carotid
3. Proximal part of Internal Carotid
4. Five branches of External Carotid:
I.SUPERIOR THYROID
II.ASCENDING PHARYNGEAL
III.LINGUAL
IV.FACIAL
Veins:
1. Internal jugular vein
Five tributaries to internal jugular veins:
I. COMMON FACIAL
II. LINGUAL
III. SUPERIOR THYROID
IV. MIDDLE THYROID
V. PHARYNGEAL VEINS
NERVES:
Two nerves related to carotid sheath:

1. Ansa cervicalis (anterior rami of C1,2,3):

embedded in the anterior wall of sheath

2. Sympathetic trunk: embedded in the

posterior wall of sheath
Three Nerves between internal
jugular vein & internal
carotid artery:

1. Vagus (10th cranial) nerve:

descends between internal
jugular vein & common
carotid artery.

2. Spinal part of accessory

(11th cranial) nerve: crosses
internal jugular vein, passes
deep to sternocleidomastoid
to reach posterior triangle.

3. Hypoglossal (12th cranial)

nerve: crosses internal &
external carotid arteries,
passes deep to posterior belly
of digastric to reach digastric
triangle.
 POSTERIOR TRIANGLE OF NECK

•Anteriorly-Sternocleidomastoid

•Posteriorly-Anterior edge of Trapezius

•Inferiorly-Middle third of the Clavicle

•Its apex is between the attachments of

Sternocleidomastoid and Trapezius to the
occiput and is often blunted, so that the
'triangle' becomes quadrilateral.

•Roof:
Investing layer of the Deep Cervical Fascia.

•Floor:
Prevertebral fascia overlying splenius capitus,
Levator scapulae and the scalene muscles.
• 2.5 cm above the clavicle, the inferior
belly of omohyoid, subdivides

• Posterior triangle into

A) Occipital Triangle
B)Supraclavicular Triangle

Floor:

• Anterior and Lateral groups of the

prevertebral musculature
 Contents:

• Fat
• Lymph nodes (level V)
• Accessory nerve
• Cutaneous branches of the
cervical plexus
• Inferior belly of omohyoid
• Branches of the thyrocervical
trunk (transverse cervical and
suprascapular arteries),
• Third part of the subclavian
artery
• External jugular vein.
 OCCIPITAL TRIANGLE

•It forms the upper and larger part of the

posterior triangle.

•it shares the same borders, except that

inferiorly it is limited by the inferior belly of
omohyoid.

•Floor (from above down)

1. Splenius capitis,
2. Levator scapulae,
3. Scaleni medius
4. Semispinalis capitis

•It is covered by the skin, superficial and

deep fasciae and below by platysma.
The spinal accessory nerve pierces
sternocleidomastoid and crosses levator
scapulae obliquely downwards and
backwards to reach the deep surface of
trapezius.
Cutaneous and muscular branches
of the cervical plexus emerge at
the posterior border of
sternocleidomastoid.

•Inferiorly, supraclavicular
nerves, transverse cervical
vessels and the uppermost part of
the brachial plexus cross the
triangle.

•Lymph nodes lie along the

posterior border of
sternocleidomastoid from the
mastoid process to the root of the
neck.
 SUPRACLAVICULAR TRIANGLE
Lower and smaller division
Shares the same boundaries, except that
superiorly it is limited by omohyoid.

•It corresponds in the living neck with the

lower part of a deep, prominent hollow,
namely, the greater supraclavicular fossa.
•Its floor contains the first rib, scalenus
medius and the first slip of serratus
anterior.
•Itssize varies with the extent of the clavicular
attachments of sternocleidomastoid and trapezius
and also the level of the inferior belly of
omohyoid.

•The triangle is covered by the skin, superficial

and deep fasciae and platysma and crossed by the
supraclavicular nerves.
Just above the clavicle,
•the third part of the subclavian
artery curves inferolaterally from the
lateral margin of scalenus anterior
across the first rib to the axilla.

•The subclavian vein is behind the

clavicle and is not usually in the
triangle; but it may rise as high as the
artery and even accompany it behind
scalenus anterior.

•The brachial plexus is partly

superior, and partly posterior to the
artery and is always closely related to
it.
•The trunks of the brachial plexus may easily
be palpated here if the neck is contralaterally
flexed and the examining finger is drawn With the
musculature relaxed, pulsation of the subclavian
artery may be felt and the arterial flow can be
controlled by retroclavicular compression against
the first rib.

•The suprascapular vessels pass transversely

behind the clavicle, below the transverse cervical
artery and vein.
•The external jugular vein
–descends behind the posterior border of
sternocleidomastoid to end in the
subclavian vein.

–It receives the transverse cervical and

suprascapular veins, which form a plexus
in front of the third part of the subclavian
artery;

–occasionally it is joined by a small vein

crossing the clavicle anteriorly from the
cephalic vein

•The nerve to subclavius crosses the

triangle

•The triangle contains some lymph nodes.

Left supraclavicular (Virchow’s) lymph
nodes are enlarge in malignancy of testis,
stomach and other abdominal organs.
(TROISIER’S SIGN)

The retropharyngeal abscess maybe

expressed in the lower part of posterior
triangle.
MUSCLES IN ANTERIOR TRIANGLE
OF NECK
 SUPRAHYOID MUSCLES
MUSCLE ORIGIN INSERTIO ACTION NERVE
N SUPPLY

Stylohyoid Styloid Greater Elevates Facial nerve

process horn of hyoid bone
hyoid bone

Digastric Digastric Intermediat Elevates the Facial nerve

(Posterior notch of the e tendon hyoid bone
belly) temporal
bone at the
base of the
skull

Digastric Intermediat Digastric Elevates the Nerve to the

(anterior e tendon fossa of the hyoid bone mylohyoid
belly) mandible muscle
MUSCLE ORIGIN INSERTI ACTION NERVE
ON SUPPLY

Mylohyoi Mylohyoid Median Elevates Nerve to

d line on the raphe and the hyoid mylohyoid
medial body of bone, base muscle
aspect of hyoid of the
mandibular tongue,
body and floor
of the
mouth

Geniohyoi Inferior Body of Elevates C1

d muscle border hyoid bone hyoid travelling
genial bone, along side
tubercle of protracts the
the hyoid bone hypoglossa
mandible l nerve
 INFRAHYOID MUSCLES
MUSCLE ORIGIN INSERTIO ACTION NERVE
N SUPPL
Y

Omohyoid Inferior Inferior Depresses the Ansa

belly: belly: hyoid bone and cervicali
Superior Intermediate larynx s (APR
border of tendon of C1,
the scapula C2, C3)
Superior
Superior belly:
belly: Lower
Intermediate border of
tendon the body of
the hyoid
bone

Sternohyoi Posterior Lower Depresses the Ansa

d aspect of border of hyoid bone cervicali
manubrium the body of following its s (APR
sterni the hyoid elevation in of C1,
bone swallowing and in C2, C3)
vocal movement s
MUSCLE ORIGIN INSERTI ACTION NERVE
ON SUPPLY

Sternothy Posterior Oblique Depresses Ansa

roid aspect of line of the larynx cervicalis
manubriu thyroid (APR of
m sterni cartilage C1, C2,
C3)

Thyrohyoi Oblique Body and Depresses Thyrohyoi

d line of greater the hyoid d branch
thyroid horn of bone of the
cartilage hyoid hypogloss
bone, al nerve
lower
border
MUSCLES IN POSTERIOR TRIANGLE OF NECK
1. LEVATOR
SCAPULAE

2. SPLENIUS CAPITIS

3. SCALENE
ANTERIOR

4. SCALENE MIDDLE

5. SCALENE
POSTERIOR
ARTERIES OF NECK
SUPERFICIAL VEINS OF NECK
LYMPHATIC DRAINAGE
Level I
Submandibular and Submental nodes.
Superiorly- Inferior border of Mandible.
Inferiorly: Hyoid bone
Bounded by the digastric muscle.

It may be
Subdivided into:

Level I a: The Submental group.

Lies between the anterior bellies of the
digastric muscles.
Boundaries
Superiorly- Symphysis
Inferiorly-Hyoid.

Level I b: The Submandibular group.

Boundaries
Superiorly- Body of mandible.
Inferiorly- Posterior belly of Digastric
Muscle. Posteriorly-Stylohyoid Muscle.
Anteriorly- Anterior belly of Digastric.
Lymph nodes contained within level I are at
highest risk in oral cancers involving the skin
of
the chin, lower lip, tip of the tongue, and floor
of the mouth.

Level II-Upper Jugular Nodes

Level II contains the upper jugular lymph
nodes that surround the upper third of the
internal jugular vein and the spinal accessory
nerve.
It includes,
1.Jugulodigastric node (Principle node of
Kuttner) -
most common node containing metastases in
oral cancer.
It is also frequently subdivided based
on the course of the Spinal Accessory Nerve.

Level II a:
Superiorly: Skull base.
Inferiorly: Hyoid bone. (Radiographically)
Surgically : Carotid bifurcation
Anteriorly: Stylohyoid muscle
Posteriorly: Vertical plane defined
by the Spinal Accessory Nerve.

Level II b:
Superiorly: Skull base
Inferiorly: Hyoid bone (Radiographically)
Surgically: Carotid bifurcation
Anteriorly: Vertical plane
defined by the Spinal Accessory Nerve
Posteriorly: Lateral aspect of the Sternocleidomastoid
muscle.
Nodal tissue within level II receives efferent
lymphatics the parotid, submandibular,
submental, and retropharyngeal nodal groups.
It also is at risk for metastases from cancers
arising in many oral and extra-oral sites,
including, the nasal cavity, pharynx, middle
ear, tongue, hard and soft palate, and tonsils.

Level III-Middle Jugular Nodes

Level III encompasses node-bearing tissue
surrounding the middle third of the internal
jugular vein.
Superiorly: Inferior border of level II (hyoid
radiographically
and carotid bifurcation surgically)
Inferiorly: Omohyoid muscle surgically and the
cricoid cartilage radiographically
Anteriorly: Sternohyoid Level III contains the dominant omohyoid
Muscle node and receives lymphatic drainage from
Posteriorly: Lateral border of the level II and level V.
sternocleidomastoid muscle.
Level IV-Lower Jugular Nodes

It contains the nodal tissue surrounding

the inferior third of the Internal Jugular Vein.
It extends from the inferior border of level III to
the clavicle.

Anteriorly: Lateral border of the Sternohyoid

muscle.

Posteriorly: Lateral border of the

Sternocleidomastoid muscle. It contains a variable
number of nodes that receive efferent flow
primarily from levels III and IV.

The retropharyngeal, pretracheal,

hypopharyngeal,laryngeal and thyroid lymphatics
also make a contribution.

Only rarely is level IV involved with metastatic

cancer from the oral cavity without involvement of
one of the higher levels.
Level V-Posterior Cervical Group

Level V makes up the posterior triangle.

Similar to levels I and II, level V may be
subdivided.

Level V a:
Begins at the apex formed by the
intersection of the sternocleidomastoid and
the trapezius.
Inferior border is established
by a horizontal line defined by the
lower edge of the cricoid cartilage.
Medially , the posterior edge of the sternocleidomastoid
forms the anterior edge and the anterior
border of the trapezius forms the posterior
(lateral) border.

Level V b: Begins at a line defined by the inferior

edge of the cricoid cartilage and extends
to the clavicle. It shares the same medial and
lateral borders as level Va.
Level V receives efferent flow from the
occipital and post auricular nodes. Its
importance in primary oral cavity cancers is
limited except when lymph flow is redirected
by metastases in the higher levels.
Oropharyngeal cancers, however,
such as tongue base and tonsillar primaries can
spread to level V nodes.

Level VI-Anterior Compartment Nodes

The anterior compartment lymph node group

is of minimal importance in primaries
originating in the oral cavity. It is made up of
the lymph node bearing tissue occupying the
visceral space. It begins at the hyoid bone,
extends inferior to the suprasternal notch, and
laterally is bound by the common carotid
arteries.