Surgical Anatomy of Head & Neck

8/15/2019 Surgical Anatomy of Head & Neck

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ASSOC PROF DR BAHARUDIN ABDULLAHDept of Otorhinolaryngology-Head Neck

Surgery

School Of Medical Sciences

Universiti Sains Malaysia

ENT Head and Neck Radiology Seminar 16-17 July 2010

Hospital Ampang


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! Thin, flat muscles which areconnected to the dermis byfasciocutaneous ligamentsand osteocutaneousligaments (zygoma andmandible)

! Innervated by the facial nerve! These muscles may often

blend into each other! Relaxed skin tension lines

run perpendicular to thedirection of muscle fibers

! During tumor extirpation,significant loss is requiredbefore a functional deficit isappreciated.


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The face is supplied by branches of the externalcarotid and the internal carotid artery

Two main branches of the external carotid:Facial

artery and superficial temporal artery

Main branches of the internal carotid that suppliesthe medial upper face and scalp is theophthalmic artery


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• Most veins in the face run parallel with theircorresponding arteries

! These veins lack valves and therefore allowbidirectional blood flow

! The facial vein can communicate with thecavernous sinus through the ophthalmic vein orthe pterygoid plexus (which drain the paranasalarea and the upper lip)

! Wound infections in this area have thepotential to gain access to the cavernous sinus


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! Innervates muscles of facial expression! Exits stylomastoid foramen and travels

through through parotid gland where itdivides into its five majorbranches:Temporal, Zygomatic, Buccal,Marginal Mandibular, Cervical

! Posterior auricular branch arises proximalto parotid

!

There is significant variability in thecourse and arborization of this nerve frompatient to patient.


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! The marginal mandibular branch exits theparotid and runs along the mandiblewhere it is covered by the platysma.

! At the anterior border of the masseter itpasses superficial to the facial artery andvein and runs along the mandible.

! At a point 2 cm from the oral commissureit takes a more superficial position, but isstill protects as long as the underlyingmuscles have not been violated.


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Sternocleidomastoid

TrapeziusDeep Cervical Fascia

Investing layer of deep cervical fascia

Prevertebral fascia

Pretracheal fascia(visceral part)Carotid sheath

Buccopharyngeal fasciaAlar fascia

Pretrachealfascia

(muscular part )

T

E


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! deep fascia of neck condenses to formfour layers:

1) investing2)pretracheal3)prevertebral4)carotid sheath


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! surrounds neck like collar! splits to enclose two muscles (trapezius &

sternocleidomastoid), two salivary glands(parotid & submandibular) and two spaces

(suprasternal & supraclavicular)


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! between angle of mandible and mastoidprocess, it splits into two laminae toenclose parotid gland, superficial lamina(parotid fascia) extends to zygomatic arch

! deeper lamina (between angle of mandible and styloid process) formsstylomandibular ligament

! forms roof of anterior and posteriortriangles of neck


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! situated in front of prevertebral musclesof neck (surrounds cervical vertebrae andassociated muscles)

! forms floor of post. triangle of neck! cervical and prox. brachial plexuses are

deep to this fascia! axillary sheath is extension of this fascia


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! triangular area in neck enclosed betweensternocleidomastoid and trapezius

! Boundaries:base: mid 1/3 of clavicle

apex: lies on sup. nuchal lineant: post border of sternocleidomastoidpost: ant border of trapeziusroof: investing layer of cervical fasciafloor: prevertebral fascia fascia covering splenius

capitus, levator scapulae, scalenus medius, andscalenus posterior


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! spinal accessory, cervical plexus,phrenic,brachial plexus

! accessory n. (CN XI) divides post triangle

into sup and inf parts, runs betweensternocleidomastoid and trapezius(supplying both), enters at 1/3 way downsternocleidomastoid

! lesser occipital n. (C2) ascends shortdistance along sternocleidomastoid before itdivides to supply skin of neck and scalp postto auricle, and sup auricle


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! supraclavicular nn. (C3-4) arise as singletrunk, which divides into med,intermediate and lat branches

! phrenic n. (C3-5) curves around latborder of scalenus ant, descendsobliquely across ant surface, deep totransverse cervical and suprascapularart, enters thorax by crossing origin of internal thoracic between subclavianart and vein


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! Innervates trapezius andsternocleidomastoid muscles

! Most vulnerable when it enters posteriortriangle of the neck at Erb ’s point

! Other nerves at risk near Erb ’s point:-Greater Auricular-Transverse Cervical-Lesser Occipital-Supraclaviular


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! Draw a horizontal line from the thyroidnotch across the neck

! Nerve exit SCM 2 cm superior to the lineand enters trapezius 2 cm inferior to theline (King and Mott, 1983)

! Draw a line from the Mastoid process tothe angle of the mandible. Then drop aperpendicular line at the mid point. Thisline will intersect the posterior border of the SCM.

! The nerve emerges within a shortdistance above this point (Salasche andBernstein, 1988).


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Arteries! subclavian (3rd part), transverse cervical,

suprascapular, occipitalVeins! external jugular! lymph nodes! muscles


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! anterior triangle - triangular area in frontof neck

! Boundaries:

ant: midlinepost: ant border of sternocleidomastoidbase: lower border of mandible, line

drawn from angle of mandible to mastoid

processapex: jugular notch


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! muscles:1)suprahyoid muscles: mylohyoid (floor

of mouth), geniohyoid (reinforce floorof mouth), stylohyoid, digastric(straplike, two bellies, intermediatetendon joined to hyoid)

2)infrahyoid muscles: omohyoid (twobellies), sternohyoid, sternothyroid(deep to sternohyoid), thyrohyoid (supcontinuation of sternothyroid)


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! Common Carotid Arteries-begins at bifurcation of brachiocephalic- arises from arch of aorta(post to sternoclavicular joints)-ascends within carotid sheath to level of

sup border of thyroid cartilage where itterminates by dividing into int & extcarotid art.


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! Internal Carotid Artery-has no branches in neck, but are

two of four major art. thatsupply blood to brain

-each passes vertically upwardsfrom common to enter carotidcanal in petrous part of temporal bone, accompaniedby plexus of sympathetic fibres

-during course through neck, liesdeep to sternocleidomastoidm and parotid gland

-enters middle cranial fossathrough the superior part of

foramen lacerum-supplies pituitary, orbit and

most of supratentorial part of brain

! External Carotid Artery-extends between C3/C4

vertebra to the neck of themandible

-runs midway betweenmastoid process and angleof mandible within theparotid gland

-terminates by dividing intotwo branches, maxillary a.and superficial temporal a.


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Common carotid

Omohyoid

Digastric

Ling ual

Sup. thyroidSup. laryngeal

Int. carotid

Ext. carotid

Ascending phary ngeal

Superficial temporal

Maxil lar y

Faci al

Pos t.auricular


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! Internal Jugular Vein-largest vein in neck (usually larger on right side than

left)-drains blood from brain and superf part of face and

neck-course corresponds to line drawn from external

acoustic meatus to med end of clavicle-commences at jugular foramen in post cranial fossa,

as direct continuation of sigmoid sinus, fromdilation at origin (sup bulb of int jugular v.)

-it runs in carotid sheath, leaves ant triangle bypassing deep to sternocleidomastoid and unites withsubclavian post to med clavicle


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Level Lymph Node Group

I Submental andsubmandibular nodes

II Upper jugular nodes (skullbase to level of carotidbifurcation/hyoid bone)

III Middle jugular nodes(carotid bifurcation toomohyoid muscle)

IV Lower jugular nodes(omohyoid muscle toclavicle)

V Posterior triangle nodes

VI Anterior compartmentlymph nodes(paratracheal/perithyroidal)

Lymph Node Groups of the Neck


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! funnel-shaped fibromuscular tube! located post to nasal cavity, mouth and larynx! divided into three parts: nasopharynx,

oropharynx, and laryngopharynx!

it is about 15 cm in length, extends from base of skull to inf border of cricoid cartilage! widest (~5cm) opposite hyoid bone, narrowest

(~1.5cm) at inf end! post wall lies against prevertral fascia, with

potential retropharyngeal space in between


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! membranes and ligaments:1)extrinsic: thyrohyoid membrane,

cricotracheal membrane2)intrinsic: quadrangular membrane

(extends between epiglottis andvestibular folds)

3)cricovocal membrane (extends between

vocal ligament and upper border of cricoid cartilage)


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! Cavity divided into three parts:-upper (vestibular) part-middle (ventricular) part: between

vestibular and vocal folds-lower (infraglottic/subglottic) part! rima glottidis: is the aperture

between the two vocal folds.


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! extrinsic muscles that move the larynxup and down during deglutition:

1)elevators of larynx : digastric,stylohyoid, mylohyoid, and geniohyoidmuscles

2)depressors of larynx : sternohyoid,sternothyroid, and omohyoid muscles

! instrinsic muscles: alterations in thelength and tension of vocal folds in theproduction of voice, and in changing thesize of rima glottidis


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! largest of endocrine glands! consists of two lateral lobes, isthmus and

occasionally pyramidal lobe! isthmus overlies 2nd, 3rd and 4th tracheal rings!

med lat lobe overlies larynx, trachea,oesophagus, inf. constrictor of pharynx andcricothyroid muscles

! post surface of lat lobe extends over carotidsheath

! infrahyoid muscles cover gland anteriorly! levator glandulae thyroideae attaches pyramidal

lobe to hyoid bone, embryological remnant of thyroglossal duct


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! Parathyroids are situated are situated on postborder, along line of sup and inf thyroid artanastomoses

! arteries:sup thyroid a. (from ext carotid a.); inf thyroid a.

(from thyrocervical trunk); and occasionallythyroid ima a.(from arch of aorta).

! Veins:sup and middle thyroid vv.(empty into int jug v);

inf thyroid vv (empty into brachiocephal v)


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! lies between body of mandible and hyoidbone

! superficial part includes submental anddigastric triangles

! deeper parts include root of tongue andfloor of mouth


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! Structures1)muscles: digastric, stylohyoid, mylohyoid, hyoglossus2)submandibular gland-mixture of serous and mucous acini-two parts: superficial and deep

-superficial: in digastric triangle, reaching upward undercover of mandible, separated post from parotid gland bystylomandibular lig

-deep: extends forwards in interval between mylohyoid andhyoglossus, post end continuous with superf part of gland,while ant end reaches as far as sublingual gland

-coverings: inner ct capsule and outer fibrous capsule(derived from deep cervical fascia)


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! submandibular duct: runs from ant deepsubmandibular gland, forward betweenmylohyoid and hyglossus

! blood supply: branches of lingual and

facial, veins follow aa.! nerve supply: derived from

submandibular ganglion (receivesparasympathetic fibres from chordatympani, lingual and sympathetic trunk)


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! largest of salivary glands(serous acini)

! covered by a capsule and a

dense fibrous tissue sheath(parotid fascia) formed by deepcervical fascia

! divided into two (superficialand deep) parts by facial n.


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! lies in fossa post to ramus of mandible! extends from external acoustic meatus to upper

part of carotid triangle! med, extends to styloid process and around

neck of mandible! post, overlaps sternocleidomastoid and extends

ant over masseter! portion of facial part often detached and called

accessory parotid gland! wedge-shaped (base above, apex behind angle

of mandible)! sup: extends upward behind TM joint into post

mandibular fossa, called glenoid process! ant: extends forwards superf to masseter


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! Parotid Duct! 5 cm long, 5mm wide! passes horizontally from ant edge, turns

med at ant masseter and piercesbuccinator, and enters oral cavityopposite crown of 2nd upper molar tooth

! Structures within the Glandfacial n (superf)

retromandibular vexternal carotid a. (deep)


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! Nerve and blood Supply! supplied by branches of external carotid

a., drains by tributaries of retromandibular v.

! secretomotor (parasympathetic): fromglossopharyngeal n. (IX), via otic ganglion

! sensory: branches from greater auricularand auriculo-temporal nn.


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ENT Head and Neck Radiology Seminar16-17 July 2010

Hospital Ampang

Surgical Anatomy of Head & Neck

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