SEMINAR ON

ANATOMICAL STRUCTURES OF THE NECK

Dr. V. RAMKUMARCONSULTANT DENTAL&FACIOMAXILLARYSURGEON

REG NO:4118 TAMILNADU –INDIA(ASIA)

ANATOMICAL S TRUCTURES OF THE NECK

Introduction

The Neck is more or less cylindrical structure connecting the head to the trunk. The

anterior midline of the neck presents a bulge whose size reflects sexual dimorphism in

that it is considerably larger in male than in female, this prominence of neck is known as

‘Adams apple’.

Importance of Neck in Human Beings

The neck contains the most important vital structures like

Arteries – Common carotid artery and its branches

Veins – External and Internal Jugular vein

Gland – Thyroid

Nerves – Hypoglossal nerve

- Vagus nerve

- Ansa Cervicalis

- Brachial Plexus

- Cervical Sympathetic chain

Contents of the Vision

1. Layers of neck.

2. Triangles of Neck.

3. Contents of the Triangles and its surgical anatomy.

4. Lymphatic system of Head and Neck and surgical anatomy.

5. Anatomical spaces of Head and Neck

Boundaries of the Neck

Above : Lower border of the mandible,

Below : Clavicle

Anterior : Median Plane

Posterior : Anterior border of the trapezius

Skin : Langer lines are horizontal lines which run around the covering of the neck.

Deep to the dermis is a very thin facial layer consisting of an areolar type of connective

tissue known as hypodermis or superficial fascia

The superficial fascia envelopes the neck just as the overlying skin and contains

with in it a paper of thin sheet of skeletal muscle the platysma.

Superficial drainage of skin

It consist of external jugular vein formed by union of the posterior auricular vein and

retro mandibular veins, just posterior to the angle of the mandible some times with in the

body of the parotid gland. The external jugular vein drains into subclavian vein.

Sensory Innervation of the neck

The skin of the neck is supplied by sensory fibrous from branch of ventral primary

rami of C2,C3,C4 of cervical plexus.

It is also supplied by the C5,C6,C7,C8 and T1 of the brachial plexus.

Sensation of the back of the neck is supplied by dorsal primary rami of C2,C3 and

C4.

The Deep cervical fascia ( fasciacoli)

The deep fascia of the necks is condensed to form the following layer

• Investing layer

• Pre tracheal layer

• Pre vertebral layer

• Carotid sheath

Investing layer of deep cervical fascia:

It lies deep to the platysma and surrounds the neck like acollar. It forms the roof of

the posterior triangle of the neck.

Attachements

Superiorly: a) External occipital Protuberance b) superior nuchal line c) Mastoid

process d) Base of the mandible e) Between the angle of mandible of the mastoid process

the fascia split to enclose the parotid gland.

Supra Clavicular Spaces

Boundaries

Posteriorly : ligamentum nuchae and spine of the vertebra C7

Other Features

The investing layer of deepcervical fascia splits to enclose

Muscles – Trapezius and Sternomastoid

Salivary glands – Parotid and submandibular

Spaces – Suprasternal and supraclavicular

The fascia form pulley to bind the tendons of the digastric and omohyoid muscles.

The suprasternal space contains

a) Sternal head of the right and Left sternomastoid muscles

b) Jugular venous arch

c) Lymphnode

d) Interclavicular ligament

The supra clavicular space is traversed by

External jugular vein

Supraclavicular nerves

Cutaneous vessels including lymphatics

Pre tracheal fascia

The importance of this fascia is that it encloses and suspends the thyroid gland.

Attachements

: Superiorly

• Hyoid bone in the median plane

• Oblique line of the thyroid cartilage

• Cricoid cartilage, more laterally

Inferiorly

Thyroid gland encloses the inferior thyroid vessels.

Other Features:

Posterior layer of thyroid capsule is thick on either side forms a suspensory

ligament of thyroid gland (Ligament of Berry). The ligaments are attached chiefly to

cricoid cartilage and may extend to thyroid cartilage they support the thyroid gland and

do not let it sink into the mediastinum.

Applied Anatomy

All swellings of the thyroid gland moves with deglutition because it is attached to

investing layer of pretracheal fascia.

Some of the malignancies of the thyroid gland are benign lesions adenoma,

malignant lesions, follicular, papillary, anaplastic carcinoma.

Prevertebral Fascia

It lies in front of the prevertebral muscles and forms the floor of the posterior

triangle of the neck.

Attachments and Relation

Superiorly : Base of the skull

Inferiorly : Extends to superior mediastinum where it is attached to anterior

longitudinal ligament and to the body of 3rd and 4th thoracic vertebra.

Anteriorly : Prevertebral facia separate from pharynx by the retro pharyngeal space

containing loose areolar tissue.

Others features

Cervical and Brachial plexus lie behind the prevertebral fascia the fascia is pierced

by the four cutaneous branches of the cervical plexus.

Axillary sheath it is the covering of prevertebral fascia the subclavian and

axillaryveins lie outside the sheath.

Relations: Brachial plexus, subclavian artery, muscles scalenus anterior and

scalenus medius.

The fascia forms a fixed base for the movement of the pharynx the oesphagus and

the carotid sheath during the movement of the neck and during swallowing.

Carotid Sheath

The sheath is not a fascia, it is condensation of fibroareolar tissue around the main

vessels of the neck.

Attachement

The carotid sheath is attached to the base of the skull at the margin of the carotid

canal and is continued down wards along the vessels to the aortic arch.

In front the lower part of the sheath is firmly attached to the deep surface of the

sternomastoid.

Relations

Ansacervicalis embedded in the anterior wall of the carotid sheath.

Cervical sympathetic chain lies behind the sheath

The sheath is overlapped by the anterior border of sternomastoid and is fused to all

the three layers of deep cervical fascia

Applied Anatomy

1. Parotid swelling are very painful due to he under lying nature of parotid fascia.

2. Submandibular gland excision should bedone after the ligation and division of facial artery ,otherwise bleeding occurs through the stylomandibular ligament.

3. Thyroid gland and its swelling move with deglutition because the thyroid gland is attached to larynx by suspensory ligament.

4. Neck infection - Behind prevertebral fascia tuberculosis is common in the cervical vertebra (pots disease ) Pus produced as a result may extend in various direction. The infections may pass down forming retropharyngeal abscess which may form a bulging in the posterior wall of pharynx. The pus may extend laterally through the axillary sheath, becomes continous in posterior triangle , or in the lateral wall of axilla. It may extend downwards into the superior mediastinum.

5. Neck infections – Infront of prevertibal fascia usually arise from suppuration. In retro pharyngeal lymphnodes. The pus forms an acute retropharyngeal abscess which bulges forward. The infection may extend down through the superior media stinum to the posterior mediastinum.

6. Division of the external jugular vein in the supraclavicular space may cause air embolism and consequence death, because the cut ends of the vein are prevented from retraction and closure by the fascia.

TRIANGLES OF NECK

The neck of the face is divided into anterior and posterior triangle by sterno mastoid.

Anterior triangle

It is a part of side of neck infront of anterior margin of sternomastoid behind the

media line of the neck and below the lower margin of the mandible.

Bony Features: Hyoid bone is the keyland mark in the upper part of neck. The

thyroid and cricoid cartilages of larynx appear below it.

Hyoid Bone

This bone belongs to the floor of the mouth, but also suspends the thyroid and

cricoid cartilages belonging to the larynx. It is a ‘v’ shaped and is suspended from the

styloid process of the temporal bone by the stylohyoid lgaments. It has a body, the

greater cornu and lesser cornu.

The hyoid bone has

a) Body

b) Anteriorsurface

c) Posterior surface

a) Lower border

b) Upper border

c) Greater cornu

d) Lesser cornu

Body it lies at the level of C3 vertebra. It is quadrilateral inshape andhas the

following surface.

Anterior surface : vertical median ridge divides the body incompletely into two halves

the attachments on each half are.

- Geniohyoid into whole body.

- Medial fibres of Hyoglossus

- Mylohyoid – linear insertion below the geniohyoid.

- Sternohyoid and omohyoid are attached to lower boarder

Posterior surface

Smooth and related to thyrohyoid membrane, Retrohyoidbursa between the

membrane and body.

- Lower border - Omohyoid

Sternohyoid

Levator glandulae thyroidae

Thyrohyoid

Upper Border :

- Hyo epiglotic ligament

- A few fibers of Genioglossus

Greater Cornu - Middle constrictor of pharynx

Hyoglossus – from lateral part of upper surface

- Stylohyoid – at the junction of greater cornu with the body.

- Fibrous loop of digastric muscles is attached lateral to stylohyoid.

Lesser Cornu : Small conical projection at junction of the body with greater cornu.

It attachement.

- Stylohyoid ligament at apex

- Chlondroglossus muscle at base

- Middle constrictor of pharynx posterolaterally.

Thyroid cartilage : Unpaired cartilage of larynx

It is at level of C 4 and C5 consists of two quadrilateral lamina joined anteriorly at

and angle to forma forward projection, the laryngeal prominence, adams apple.

Applied Anatomy

Hyoid bone will be fractured in hang over (suicide conditions). It is an important

evidence of forensic medicine.

Cricoid Cartilage

It lies at level of C6 vertebra. It gain attachment to the cricothyroid muscle which is

inserted into the posterior part of the lower border of the thyroidlamina and the anterior

surface of the inferior cornu of hyoid cartilage.

Subdivisions of anterior Triangle

1. Digastric Triangle

2. Carotid Triangle

3. Muscular Triangle

4. Submental Triangle Half of the triangle is shared by the anterior triangle of both sides.

Digastric Triangle Ant: ant belly of digastric

Post : Posterior belly of Digastric

Roof : Skin, superficial fascia, platysma with in the superficial fascia are the facial

vein cervical branch of facial nerve – and branches of transverse cervical nerves (C2 , C3)

Floor Hyoglossus and middle constrictor posteriorly mylohyoid anteriorly overlapping

the hyoglossus. Floor is covered by the deep layer of superficial lamina of cervical fascia.

• Contents – lower part of submandibular salivary gland.

• Sub mandibular lymphnodes

Facial vein – pierces the deep fascia at lower border of the mandible across the

salivary gland.

Facial artery curves round the lower border of the mandible enters the face after

piercing the deep fascia.

Mylohyoid nerve : The nerve lies on the anterior surface of mylohyoid and supplies

mylohyoid muscle anterior belly of digastric.

Submental Vessels

They run forward on the inferior surface of submandibular salivary gland near the

mandible.

Hypoglossal nerve

The nerve is accompanied by the vein and run across the hyoglossus muscle

Lingual Artery

The artery is present on the deep side of the posterior belly of digastric

Applied anatomy

The sub mandibular group lymphnodes are affected in inflammation and in

malignancies.

The preservation of facial artery in surgical procedure

Preservation of marginal mandibular nerve in fracture of mandible.

Carotid Triangle

Boundaries

Superiorly : posterior belly of digastric

Inferiorly : Superiorly belly of omohyoid

Floor : Hyoglossus

• Thyrohyoid

• Middle and inferior constrictors

Roof - Skin

• Superficial fascia – containing platysma, cervical branch of facial nerve and

transverse cervical nerve.

• Investing layer of deep cervical fascia.

Contents

Carotid sheat which encloses. Common cartotid artery, vagus nerve internal jugular

vein, sympathetic trunk is embedded in the postero medial wall of the carotid sheath.

The Common carotid ascends from just behind the lower angle of the triangle. It is

divided in to external and internal carotid arteries at the level of upper border of thyroid

cartilage.

The externalcarotid ascends anteromedial to internal carotid and gives of following

branches.

1. Ascending pharyngeal

2. Superior Thyroid

3. Lingual

4. Facial

5. Occipital

6. Posterior Auricular

7. Maxillary artery

8. Superficial temporal artery

Vagus nerve

It descends in the carotid sheath posterolateral to the internal and common carotid

arteries, it has the following branches

1. Pharyngeal Branches : It runs inferomedially between both the carotid to join the pharyngeal plexus on the middle constrictor of pharynx.

2. Superior laryngeal nerve : Runs on a deeper plane and lies deep to both arteries, it divided into internal and external laryngeal nerves.

3. Accessory nerve : Runs down wards and backwards across the upper part of the triangle superficial to internal jugular vein.

4. Hypoglossal nerve : Descends downwards between the internal jugular vein and internal carotid artery and then runs forward crossing both the carotid and forms a loop of the lingual artery and disappear under the digastric tendon.

Pharyngeal plexus

It is formed by pharyngeal branches of vagus, glossopharyngeal nerve, branch from

superior cervical ganglion.

Applied Anatomy

1. Baro receptor: Carotid sinus a fusiform dilatation involving the bifurcation of common carotid and beginning of internal carotid.

- The afferent limb of carotid reflex is mediated by the carotid branch of glosso pharyngeal nerve – for controlling intracranial pressure.

- Efferent limb of inhibitory carotid reflex is mediated by vagus nerve.

Supra Ventricular Tachy cardia is susceptible to vagal effects and may be converted

into normal sinus rhythm by carotid massage.

Carotid body : Neuro vascular structure lying between bifurcation of common carotid

artery is very vascular. It is a chemo receptor sensitive to blood oxygenation and to lesser

extent partial pressure of Carbon-di-oxide .

Potato tumors or carotid body tumors or Chemodectoma : It is difficult to remove

because of their location, they are associated with slow pulse and attacks of fainting due

to pressure on carotid sinus.

Internal jugular vein is one of the vital structure in the neck to prevent damage

during surgical dissection of neck tumors.

Muscular Triangles

Boundaries : above : superior belly of omohyoid

Below: Anterior border of sternomastoid

Contents

Sternohyoid

Sterno thyroid

Thyro hyoid

They are known as the strap muscles of the neck.

The main importance of the triangle is that it overlies the thyroid gland

The omohyoid, steronohyoid, sternothyroid, thyrohyoid are known as infrahyoid muscles.

They are innervated by C1, C2, C3 (Cervical nerve)

Actions : Muscles are involved swallowing and phonation as they fix the hyoid bone

to enable other muscles.

Sub mental triangle or suprahyoid region

Boundaries : Laterally – Anterior belly of digastric

Posteriorly : Body of hyoid bone.

Floor : Two mylohyoid muscles and median raphe between them

Covering layer : Skin, platysma, deepcervical fascia. Anterior jugular vein begins in

the superficial fascia deep to platysma.

Contents : Submental lymph nodes

Clinical Application : Infection of the median region of the floor of mouth, tip of the

tongue or the incisorteeth causes pain ful enlargement of the submental lymphnodes.

Median Region of the front of the Neck

It is divisible in to suprahyoid and infrahyoid regions. The submental triangle which

forms the region

Infrahyoid region is in the middle between the infrahyoid muscles of the two sides

the following structures are present above downwards.

• Median thyroid ligament – connects upper border of thyroid cartilage to upper border of hyoid bone.

• Laryngeal prominence

• Cricothyroid ligament

• Cricothyroid muscle

• Isthmus of thyroid gland

Supro sternal space of burns – a fascial space formed by splitting of the investing

layer of deepcervical fascia just above the suprasternal notch contains some lymph nodes

jugular arch connecting lower end of anterior jugular vein. Sternal heads of orgin of

sternomastoid and interclavicular ligament.

Sterno mastoid muscle

The muscle pass obliquely upwards on the side of the neck. It is along bulky muscle.

Origin : Arises by two head.

Sternal head : Arises by a rounded tendon upper part of manubrium sterni . It is directed upwards and laterally.

Clavicular head : Superior border and anterior surface of medial one third of clavicle.

The two head of the muscles are separated by triangular interval in which the

internal jugular vein lies.

Insertion

Sternal head : Sterno mastoid part inserted into tip of the mastoid process.

Clavicular head: Cleido occipitalis part is formed by the posterior fibres of the

clavicular head and is inserted into the superior nuchal line with sterno occipitalis fibres.

Relations

Superficial

1. Skin, superficial fascia containing platysma.

2. Investing layer of deep cervical fascia

3. Greater auricular nerve

1. External jugular vein

Deep relation

• Infrahyoid muscles

• Carotid sheath

• Subclavian artery

• Scalenus anterior muscle.

Crossing the muscle transversely from above downwards

• Inferior belly of omohyoid

• Transverse cervical artery

• Subclavian vein

Middle part

Common carotid artery

Internal jugular vein

Ansacervicalis

Upper part of brachial plexus.

Upper Part

• Mastoid process

• Cervical plexus

• Posterior belley of digastric

Nerve supply

• Spinal accessory nerve.

• Ventral rami of C2 and C3

Blood supply

Sternomastoid from super thyroid artery

Two sternomastoid from occipital artery at the level of hyoid bone.

Action

Rotation of head to carry the face to opposite side

Raising the head while the person is lying flat on his back.

Lateral flexion and contra lateral rotation, it helps in looking to side and upwards.

Sternomastoid muscle involves in accessory respiration.

Applied Anatomy

Spasm of the muscle is one of the cause of flexion deformity of the neck known as

wry neck or torticolis. In this the case ear lies close to the tip of the shoulder. And the

chin is rotated to the opposite side.

Posterior Triangle

Boundaries

Anterior : Posterior border of sternomastoid

Posterior : Anterior border of trapezius

Inferiorly : Middle third of clavicle

Superiorly : Apex by meeting point of the trapezius and sternomastoid.

Subdivisions: The inferior belly of omohyoid crosses the lower part of the triangle

and divides it in to two parts.

i) Occipital Triangle

ii) Subclavian Triangle

Roof : Skin, Superficial fascia with platysma, investing layer of deep cervical fascia.

Platysma : Thin flat sheet of muscle embedded in the superficial fascia .

Origin : from skin, fascia below the clavicle over the upper part of deltoid and

pectoralis major.

Insertion : In to the outer surface of mandible just above the inferior margin and

into the lower facial muscles around the angle of the mouth.

Action : Wrinkles skin of the neck and helps to open the mouth.

Nerve supply : Cervical branch of facial nerve

Floor of the posterior Triangle

1. Splenius capitis

2. Levator scapulae

3. Scalenus medius

Contents of Posterior triangle:

Muscle : splenius capitis , levatorscapulae,posteriorscalene muscle

Veins : external Jugular , transverse cervical , suprascapular

Arteries : Occipital, subclavian, transverse cervical, Suprascapular,

Nerves : Spinal Accessoy nerve, trunks of brachial plexus,

Lymphnodes

Occipital

Retroauricular

Superficial cervical

Upper deep cervical

Clinical Application

1. Erbs point union of C5 and C6 of brachial plexus

2. Radial nerve paralysis (wrist drop)

3. Third part of subclavian artery is prone for aneurysm formation.

4. Cervical rib may elevate subclavian artery and the branch of T1 which contributes the formation of lower trunk of brachial plexus. The pressure on post ganglionic T1 sympathetic fibers causes vaso constriction, the small muscles of the hand has numbness which later causes paralysis of the hand.

Lymphatic Driange of the Neck

They are Classified in to superficial and Deep

Superficial Nodes : The nodes are arranged in the form of a circle around the neck

called the pericervical collar.

Pericervical collar are horizontally disposed nodes and so are arranged in the form

of a circle at the junction of head and neck. They are divided into.

Submental nodes: These or four small nodes which lie just beneath the chin between

the anterior bellies of digastric on the inferior aspect of mylohyoid they drain the tip of the

tongue floor of the mouth, the lower incisor teeth, lower lip.

Submandibular Nodes: They lie beneath the deep fascia of the submandibular

salivary gland. These nodes drain an extensive area of lips, cheek, anterior part of scalp,

upper and lower teeth, gingiva, the side of the tongue, the anterior part of nasal cavity

and paranasal sinus.

Preauricular lymph Nodes: They lie in front of the tragus of the ear and are usually

superficial to the parotid gland. They drain in the skin of the anterior part of the scalp,

the temple, pinna and external acousticmeatus.

Mastoid nodes: they lie in the mastoid process behind the root of auricle, they drain

the back of pinna and external auditory meatus.

Occipital nodes : They lie at the apex of the posterior triangle of the neck. They

drain back of the scalp and back of upper part of neck.

Facial nodes: The nodes are present along the facial vein one of these nodes lies on

the buccinator muscle close to the facial artery and known as buccal node.

Infrahyoid nodes: They lie on the thyrohoid membrane they drain the larynx above

the level of vocal cord.

Pre tracheal nodes : They lie on the trachea close to inferior thyroid veins they

receive lymphatics from the anterior cervical nodes.

Deep Cervical Nodes : These nodes drain in the deeper tissue of the neck. They are

placed around the carotid sheath from the base of the skull to the root of the neck, deep

to sternomastoid.

Superior deep cervical nodes: These nodes lie above the level of omohyoid, they

drain, the parotid, submandibular nodes, the root of tongue, upper lateral part of

thyroidgland.

They consistof jugulo digastric node, it is the chief node of draining the palatine

tonsil.

Waldeyer internal ring : It is a lymphoid tissue of the entrance of pharynx it is

formed.

Superiorly : pharyngeal tonsil

Inferiorly : Lingual tonsil

Laterally : palatine and tubal tonsil

Inferior deep cervical nodes: These nodes lie below the level of the thyroid cartilage

and the bifurcation of the common carotid artery, they drain the superior deep cervical

nodes, lower lateral part of thyroid gland, lower part of larynx.

Jugulo omohyoid belong to this group and it lies above the inferior belly of

omohyoid. “It is an important lymphatic drainage of tongue.

Paratracheal nodes: These lie between the trachea and oesophagus close to

recurrent laryngeal nerve . They are extension of inferior deep cervical nodes.

They receive lymphatic drainage from thyroidgland, cervical part of oesophagus,

trachea and neighbouring vessels.

Applied anatomy

Pain ful enlargement of submandibular nodes are common in infection.

Malignancy : The lymphnodes are hard in consistency and may be fixed to the

under line structures.

Occipital nodes: Enlarge in German measles.

Enlargement of jugular digastric node in pharyngeal or tonsilar involvement.

Lymphnodes of the Neck

They are classified according to the following levels

Level 1 : Lymphnodes of the submandibular triangle which includes those in the

submental region, those adjacent to sub mandibular gland above the digastric muscle,

prevascular lymphnodes adjacent to the facial artery and vein.

Level 2, 3 and 4: Represent deep jugular lymphnodes along the internal jugular vein

extending from the base of the skull to the supra clavicular region, They are divided into

three levels.

Upper third – Level 2

e.g Jugulodigastric and juguloomohyoid

Middle third upto the tendon of omohyoid muscle is level 3

Those in the deep jugular chain cauded from the omohyoid tendon up to clavicle are

level 4.

Level 5. Lymphnodes in the posterior triangle of the neck and contain in those in

the floor of posterior triangle of the neck (e.g. Sternomastoid and supraclavicular

lymphnodes.)

Levelling of Lymphnodes is prognosis for primary carcinoma of the oral cavity. The

prognosis is significantly worse with increasing level of involvement of lymph nodes by

metastatic cancer. The sequential fashion.

Level 1 and 2 followed by 3 and 4 then level 5

It would be rare to find involvement of Level 5 for primary oral carcinoma in the

absence of metastatic disease at levels 1 through 4.

Lymph nodes dissection

Modified radical neck dissection Type 1

Level 1 to level 5

Structure preserved

Spinal accessory nerve

Structure excised : sternomastoid muscle, internal jugular vein, submandibular gland.

Modified radical neck dissection Type 2

Lymph nodes excised : Level 1 to Level 5

Structure preserved : sternomastoid and spinal accessory nerve

Structure excised : Internal Jugular vein

Modified radical neck dissection Type 3

Lymph nodes dissected - Level 1 to level 5

Structures excised - Submandibular gland

Structures preserved – Sternomastoid muscle

Internal jugular vein and spinal accessory nerve

ANATOMICAL S PACES

Sublingual space : The Space lies above mylohyoid muscle

Roof – Mucous Membrane of floor of mouth

Floor – Mylohyoid

Laterally – Inner surface of body of mandible above the mylohyoid line.

Medially – Geniohyoid, Genioglossus

Contnts : Sublingual gland, sub mandibularduct, deep part of sub mandibular

gland, hypoglossal nerve, lingual nerve, terminal branches of lingual artery.

Floor – mylohyoid muscle

Roof – skin, platysma, deep cervical fascia,

Laterally – Anterior belly of digastric

Contents : Anterior Jugular vein, submental lymph nodes.

Submandibular Space or Digastric Space

It lies postero lateral to submental space

Floor – Mylohyoid and Hyoglossus

Roof – skin and platysma

Posteroinferiorly – Stylohyoid, post belly of digastric

Anterio inferiorly – Anterior belly of digastric.

Space – closed by investing layer of deep cervical fascia

Superior layer – inferior border of the mandible

Deep layer – mylohyoid line

Contents

Submandibular gland

Facial artery

Nerve to mylohyoid

Mylohyoid vessels

Applied anatomy

Ludwigs angina is the common complication of sub mandibular, sublingual and sub

mental space infection. It is a life threatening condition which requires immediate

surgical treatment.

Masticator space infection

The space includes along the border of the mandible, ramus of the mandible,

muscles of mastication.

The fascia splits into outer sheath covers the external surface of the mandible,

masseter and temporalis muscles, the inner sheath covers the inner border and is

attached at the mylohyoid ridge.

Communications

Posterior it communicate with the parotid space laterally and para pharyngeal space

medially superiorly it continuos with the temporal pouches.

Applied anatomy

Trismus is the common complication of masticator space infection . The infection

can spread from 1st , 2nd and 3rd molar teeth.

Buccal Space Infection:

This Space exist between buccinator and masseter muscle. It contains buccal pad of

fat which extends upwards and inwards between the muscles of mastication.

Applied anatomy

Periapical abscess is a common complication of this space. Which is related to

infection from maxillary first and second molar

Infection of Temporal pouches

They are classified into superficial and Deep.

Temporal pouches are the spaces in relation to temporalis muscle.

Deep pouch – It lies between the skull and temporalis muscles.

Inferiorly the two pouches communicate with the infra temporal space at the level of

zygomatic arch.

Applied anatomy

Infection are secondary to masticator, infratemporal and pterygopalatine space.

Infratemporal Space

It lies inferior to the temporal pouches below the horizontal line drawn at the level of

zygmoatic arch. Laterally it is bound by zygomatic arch and ramus of the mandible.

Medially : Lateral surface of lateral pterygoid and lateral wall of pharynx.

Posteriorly : parotid gland

Anteriorly : Posterior surface of maxilla

Superiorly : Infra temporal crest of great wing of sphenoid.

Contents

1. Lateral pterygoid muscle

2. Inter maxillary artery

1. Mandibular nerve

2. Buccal nerve

3. Lingual Nerve

4. Chordatympani nerve

5. Pterygoid plexus

6. Pharyngeal plexus

Applied Anatomy

Infections from maxillary first, second and Third molars can cause infection of this

space.

Parotid Space

It is formed by splitting of investing layer of deep cervical fascia. It contains the

parotid gland as well as lymph nodes. The fascia on the external surface of the gland is

thick. The fascia on the internal side is thin and in complete .

Communications

Superiorly it communicate with lateral pharyngeal space. It forms a strong band

medially called the stylomandibular ligament that separates parotid space from

submandibular space.

Applied anatomy

Mumps and infectious viral disease can cause bilateral enlargement of parotid gland.

Benign and malignant tumors of the parotid gland may affect this space. Example -

Plemorphic adenoma, adenoid cystic carcinoma may affect the space.

Lateral Pharyngeal Space:

It is cone shape space the base of cone lying at base of skull and the apex at carotid

sheath at the level of hyoid bone. This space lies lateral to pharynx, and medial to

submandibular, pterygomandibular and parotid space.

Laterally – Medial pterygoid and parotid gland

Medially – Superior constrictor of pharynges

Post : Prevertebral muscles

Anteriorly – Pterygomandibular raphe

Superiorly – Petrous part of temporal bone with foramen lacerum with jugular

foramen

Inferiorly – the Stylohyoid and capsular attachment of parotid gland.

Styloid process divides the space in to two compartments

Anterior compartment – Deepcervical and facial

Posterior Compartment – Carotid sheath

- Internal carotid artery

- Internal Jugular vein

- Vagus nerve

Applied anatomy

Infection of the lateral pharyngeal space may cause erosion of the internal carotid

artery and may cause fatal to life.

REFERENCE BOOKS

1. Grays Anatomy

2. Last Anatomy

3. Chaurasia

4. Colour Atlas of Anatomy

5. Infection by Topazian

SPECAL ACKNOWLEDGEMENT TO

My Department Professor, Reader, Lecturer.

My Beloved Parents and My Batch Mates

I am extremely thankful to

1. Dr. Suresh Kannan

2. Dr. Saravanan

3. Dr. Srivatsa

My Senior colleague for their guidance

Thank you