Head & Neck

Summary of module Facial skeleton

Fracture of the roof of the orbit – subconjunctival haemorrhage

Direct bruising of the soft tissues – blood tracking down deep to the aponeurotic layer of

scalp (black eye)

Fracture anterior skull may be accompanied by bleeding (into nose & mouth) & CSF leakage;

implies tearing of meninges (subarachnoid exposure – risk of meningitis

Fracture of middle skull may be accompanied by bleeding (into mouth &/or CFS leakage

from the ear) & injury to facial & auditory nerves.

Cervical spine injuries – Dislocation

Vertebrae stacked on top of each other – relatively less force will cause dislocation; severe

dislocation may causes serious injuries by compressing the spinal cord

Dislocation because of relatively horizontal intervertebral facets

Dislocation may result from sudden forward jerk during automobile accidents.

Cervical spine – other injuries

Fracture of the dens – displacement may injure the spinal cord may cause quadriplegia or

brainstem injuries death

Narrowing of IV foramina (aging process) – compression of nerve roots (neck pain)

Osteophyte formation near vertebral joints – may affect nerves – pain in dermatomes &

spasms of muscles (myotomes)

Hyperextension of neck (whiplash) may cause ligament tears, fractures, disc rupture,

muscles & blood vessel injuries

Hyperflexion during head-on collision may rupture lower IV discs.

Cranial Meninges

Three spaces – two potential

Extradural arterial haemorrhage in the space – head trauma can detach the dura from the

bone without fracture ( blood from meningeal vessels)

Subdural haemorrhage (venous) following head trauma (hard blow) – fracture of cerebral

veins entering sinuses

Subarachnoid haemorrhage (usually arterial) following head trauma (cranial fractures &

cerebral lacerations) bleed into subarachnoid space (irritation – headache, stiff neck & loss

of consciousness)

The layer between the arachnoid mater & pia mater is the subarachnoid space this contains

CSF. This fluid filled space helps maintain the balance of ECF in the brain.

Anterior & middle cranial fracture may cause bleeding & leakage of CSF due to meningeal

tears

Main muscle groups & their nerve & blood supply

Muscles of facial expression – cranial nerve VII – facial nerve)

o Inflammation of the nerve near its exit from the cranial cavity – most common non-

traumatic cause of facial paralysis (facial nerve palsy)

o Superficial branches subject to injury in wounds, cuts & child birth

o Nerve vulnerable to injury during surgery on the parotid gland or in disease of the

gland.

Muscles of mastication – cranial nerve VIII – trigeminal nerve (mandibular division)

Head & Neck – arteries – main artery is the external carotid major branch is the facial artery

which can be felt on inferior border of mandible.

Facial vein – main venous drainage; drains into internal jugular vein; also drains via the ophthalmic

veins into the cavernous sinus; emissary veins also drain into dural venous sinuses

Neck – deep cervical fascia

Structures in the neck – compartmentalised by cervical fascia

Allows movement with ease during movements e.g. swallowing, twisting

Form natural cleavage planes allowing separation of tissues during surgery

Determine the spread of infection between layers

Superficial fascia – thin fatty membrane enclosing the platysmaa muscle

Deep fascia – three layers

Investing layer – invests all muscles of the neck; attached to all bony landmarks at the upper

& lower margin of the neck; above to the mandible, zygomatic arch, mastoid process &

superior nuchal line; below to the manubrium, clavicle, acromion, scapular spine &

posteriorly to the ligamentum nuchae

The ligamentum nuchae, is found in the cervical region & is a continuation of the

interspinous & supraspinous ligaments of the thoracic & lumber vertebrae. It is thickened

fibroelastic tissue that attaches to the external occipital protuberance & the posterior

border of the foramen magnum to the spinous processes of the cervical vertebrae. It

preserves the normal curvature of the cervical spine.

The pretracheal layer – encloses the visceral compartment of the neck & extends from the hyoid

bone to the fibrous pericardium. Encloses larynx & trachea, pharynx & oesophagus & thyroid gland.

Encloses the infrahyoid muscles also forms the carotid sheath.

The prevertebral layer – passes from the vertebrae & prevertebral muscles behind the oesophagus,

the pharynx & the great vessels. Above it is attached to the base of the skull, laterally it covers the

scalene muscles & the emerging brachial plexus & subclavian artery – these structures carry with

them a sheath from the prevertebral fascia which forms the axillary sheath. Inferiorly, the fascia

blends with the anterior longitudinal ligament of the upper thoracic vertebrae in the posterior

mediastinum.

Spread of infection between layers- investing layer helps to prevent the spread of abscesses

If infection occurs between the investing layer & the muscular part of the pretracheal fascia

surrounding the infrahyoid muscles infection will not usually spread beyond the upper part of the

manubrium. If it occurs between the investing fascia & visceral part spread into the thoracic

cavity anterior to the pericardium.

Pus from abscesses posterior to the prevertebral layer may extend laterally in the neck & form a

swelling posterior to SCM; the pus may perforate the layer & pass into the retropharyngeal space

producing a bulge in the pharynx cause difficulty in swallowing & speech

Infection in the retropharyngeal space into superior mediastinum

Borders of the posterior triangle:

Anteriorly by the posterior edge of the SCM

Posteriorly by the anterior edge of trapezius

Its base is the middle 1/3 of the clavicle

Its apex is the occipital bone just posterior to the mastoid process where the attachments of

the trapezius & SCM come together.

Neurovascular structures in the posterior triangle; external jugular; 3rd part of subclavian artery;

dorsal scapular artery (branch of subclavian); cervical & Suprascapular artery (both branches from

the thyrocervical trunk); the subclavian vein; Nerves: Accessory nerve (XI); branches of cervical

plexus, components of the brachial plexus, & branches of the brachial plexus.

Borders of the anterior triangle:

Anterior border of the SCM laterally

The inferior border of the mandible superiorly

The midline of the neck medially.

Neurovascular structures in the anterior triangle:

Vessels: Common carotid & their branches & the ICA. Also IJV & its tributaries. The carotid sinus,

carotid body

Nerves: Facial nerve (VII), Glossopharyngeal nerve (IX), Vagus nerve (x), Accessory nerve (XI),

Hypoglossal nerve (XII)

Session 1 The Cranium

The cranial bones form the calvaria (dome) & the cranial base. The bones of the calvaria consist of 2

layers of compact bone separated by a layer of bone marrow, the diploe. The bones of the cranial

base articulate with the atlas, the facial skeleton & the mandible. The cones of the cranium are

joined by sutures (coronal, sagittal & lambdoidal). The pterion, which lies on the lateral aspect of the

skull, is the thinnest part of the calvaria.

Clinical:

Fractures of the skull are common in the adult. A severe, localised blow results in a

depressed fracture, in which a fragment of bone may compress or injure the underlying

brain. Trauma to the vault often result in radiating linear fractures, the fracture lines

radiating away from the point of impact in more than 2 directions

Parts of the cranium that are covered by thick muscle (e.g. squamous part of the temporal

bone) are thin & are thus fractured easily causing injury to the underlying structures. Thus a

lateral fracture at the pterion may lacerate the middle meningeal artery & cause an epidural

arterial haematoma between the skull & the periosteal layer of the dura mater; the

haematoma exerts pressure on the underlying cerebral cortex.

A subdural haematoma develops between the dura mater & arachnoid mater. The

haematoma results from venous bleeding, usually from torn cerebral veins where the enter

the superior sagittal sinus. Most occur in the young & elderly. The increased CSF space in

patients with cerebral atrophy results in a greater than normal stress on the cerebral veins

entering the sagittal sinus. Hx – trivial injury followed by an insidious low of consciousness

In a countercoup fracture, the fracture occurs on the opposite side of the cranium rather

than at the site of impact

The base of the skull seems strong but gets fractured because it has the body connected to it

that can deliver a lot of force.

The emissary veins connect superficial veins of the scalp with the diploic veins of the skull

bones with intracranial venous sinuses. Infection of the scalp may spread to the skull bones

via these veins causing osteomyelitis.

The Facial Skeleton

The main features of the anterior aspect of the skull are the frontal & zygomatic bones, orbits, nasal

region, maxillae & mandible.

The frontal bone forms the skeleton of the forehead & articulates with the nasal & zygomatic bones;

the frontal bone, which also articulates with the lacrimal, ethmoid & sphenoid bones, forms the roof

of the orbit & part of the floor of the cranial cavity. Just above the orbital margin is a sharp bony

ridge, the supraciliary arch. The zygomatic bones which lie of the inferolateral sides of the orbit

articulate with the frontal, sphenoid, temporal bones & the maxillae.

Clinical:

Car accidents, fist fights & fall are common causes of facial fractures. The most common

involve the nasal bones because of the prominence of the nose. Maxillofacial fractures

occur as a result of massive facial trauma. A hard blow to the lower jaw often results in the

fractures of the neck of the mandible & its body & may be associated with the dislocation of

the temporomandibular joint.

A trauma or a blow to the sharp supraciliary arches may cause laceration of the skin & result

in profuse bleeding. Skin bruising around the orbit causes tissue fluid & blood to accumulate

in the surrounding CT causing a black eye

Paget’s disease occurs in the elderly. The bones most frequently involved are the pelvis,

femora, vertebrae & skull. There is a rapid irregular & exaggerated reabsorption &

replacement of bone, causing thickening, swelling & increased vascularity, often with severe

pain. When the skull is affected, it slowly enlarges, as do the jaws the maxilla more

frequently than the mandible that necessitates adjustment to dentures/ The teeth may

become displaced & become fused with bone, complicating extractions/ Oral surgery may

become complicated by severe haemorrhage.

The cervical spine

C1 to 7 They bear less weight than vertebrae further down. The atlas supports the skull at the

atlanto-occipital joint. The axis is the strongest of the cervical vertebrae because C1, carrying the

skull, rotates on it. The dens projecting superiorly from C2 is held in position by a transverse

ligament of the atlas that prevents horizontal displacement of the atlas.

C3 – 6 are characterised by large vertebral canal because of the cervical enlargement of the spinal

cord for the innervation of the upper limb. The spinous processes of C3-6 are short & bifid. C7

(vertebra prominens) is characterised by long spinous process that can be palpated on the back of

the neck.

The foramina in the transverse processes of the cervical vertebrae transmit the vertebral arteries on

their way to supply the brain; the transverse processes end laterally in two projections (anterior &

posterior tubercles). The anterior tubercles of C6 are called carotid tubercles because the common

carotid arteries may be compressed against them to get a pulse & to control bleeding.

Clinical

As the bodies of the cervical vertebrae can be dislocated in neck injury with less force than is

required to fracture them. Slight dislocation may not damage the spinal cord because of the

large vertebral canal in the cervical region; however, severe dislocation may cause serious

injuries.

Fracture of the dens may occur in a fall on the head; displacement of the fractured dens may

injure the spinal cord, causing quadriplegia or the medulla of the brainstem, causing death.

Age changes in the intervertebral discs result in narrowing of the intervertebral foramina

that may cause compression of the spinal nerve roots causing neck pain.

Hyperflexion of the cervical region during a head-on collision could result in the rupture of

lower cervical intervertebral discs (e.g. C5/C6 & C6/C7 resulting in compression of the spinal

roots C6 & C7 pain is felt in the neck, shoulder, arm & hand. During severe hyperextension of

the neck (whiplash) could result in tearing of anterior & posterior longitudinal ligaments,

fracture of the cervical spinous processes, disc rupture, neck muscles & blood vessel injuries.

The cervical vertebrae are prone to dislocation due to almost horizontal alignment of the

articular facets between adjoining vertebrae.

Joints of the vertebral arches (zygapophyseal joints) are close to the intervertebral foramina

through which spinal nerves emerge from the vertebral canal. When these joints are affect

by osteoarthritis, the related spinal nerves are affected causing pain along the distribution

patterns of the dermatomes & spasm in the muscles derived from the associated myotomes.

Common disorders of the skull & cervical spine

Skull fractures:

Simple fracture is a fracture without damage to the skin

Linear fracture resembles a thin line, without splintering, depression or distortion of bone.

Depressed fracture results in the bone being pushed towards the brain

Compound fracture involves a break in or loss of skull & splintering of the bone accompanied

by brain injury & bleeding.

The skull is prone to fracture at certain anatomical sites – squamous temporal & parietal bones over

the temples & sphenoid air sinus, the foramen magnum & in the inner parts of the sphenoid wing at

the skull base; the middle cranial fossa is the weakest with thin bones & multiple foramina; the

cribriform plate of the ethmoid bone & the roof of the orbits in the anterior cranial fossa; areas

between the mastoid & dural sinuses in the posterior cranial fossa.

Symptoms of fractures include bleeding from wound, ears, nose, or around eyes, brusing, draining of

CSF from ears or nose, swelling, confusion, convulsions, difficulties with balance, drowsiness,

headache, loss of consciousness, nausea, vomiting, visual disturbances, stiff neck & slurred speech

The most common sites of cervical spine injuries are at the level of C2, C6 & C7. The most fatal

injuries occur in the upper part of the spine at C1 or C2.

Arteries

Most arteries supplying the face are branches of the ECA. The facial artery is the major arterial

supply to the face. The ECA as the superficial temporal artery & the maxillary artery. The facial vein

forms the major venous drainage of the face & drains into the IJV. Superficial temporal vein,

maxillary vein & other veins form the external jugular vein. Both internal & external jugular veins

drain into the subclavian vein.

The pulse of the facial artery inferior border of the mandible. Because the artery has many

anastomoses with other arteries of the face, in the event of laceration of the artery on one side of

the face, it is necessary to compress both the arteries to stop the bleed.

The neck

Structures in the neck are compartmentalised by layers of cervical fascia that allows the structures

to move & pass over one another with ease as when swallowing & twisting the neck. The superficial

fascia lies between the skin & investing three layers of deep cervical fascia.

The most superficial layer (investing layer) of the deep cervical fascia surrounds the entire neck deep

to the skin. It encloses the SCM & TM, Submandibular & parotid glands

The next layer – pretracheal layer) is thin & limited to the anterior part of the neck. Inferiorly it

extends into the thorax where it blends with the fibrous pericardium. It forms a muscular layer

enclosing infrahyoid muscles & a visceral enclosing the thyroid gland, trachea & oesophagus.

Laterally it blends with the carotid sheaths; each carotid sheath is a tubular fibrous structure that

extends from the base of eh cranium to the root of the neck & contains the CCA, IJV & vagus nerve

(10th CN)

the innermost layer – prevertebral layer – forms a sheath for the vertebral column & muscles

associated with it. This layer extends from the base of the cranium to the T3 & extends laterally as

the axillary sheath that surrounds the axillary vessels & brachial plexus.

the layers of deep cervical fascia form natural cleavage planes allowing separation of tissues during

surgery. The deep facial layers also determine the direction in which abscesses in the neck may

spread.

If an infection occurs between the investing layer of the fascia & that surrounding the infrahyoid

muscles, it will not spread beyond the manubrium.

However, if infection occurs between the investing & pretracheal layer, it can spread into the

thoracic cavity to the pericardium.

The retropharyngeal space is a potential space between the prevertebral layer of fascia & the fascia

surrounding the pharynx superficially. It is larger & a major pathway for the spread of infection from

the neck to the thorax

Pus from an abscess lying behind the prevertebral layer of deep cervical fascia may extend laterally

in the neck. It may perforate the fascial layer & enter the retropharyngeal space producing a bulge

(retropharyngeal abscess) in the pharynx. This bulge may cause dysphagia & dysphonia (problem in

speech)

Session 2 – The orbit, the eyeball & Common disorders The orbit is pyramidal in shape

Apex: optic canal (for optic nerve)

Base: orbital margin surrounding the opening

Roof: orbital part of frontal bone

Medial: lacrimal & ethmoid bones

Lateral: Zygomatic & greater wing of sphenoid (thick)

Floor: orbital surface of maxilla (underneath maxillary sinus)

Fissures/canals optic canal, superior orbital

fissure & inferior orbital fissure.

Lacrimal Apparatus:

Lacrimal gland – lateral part of roof of orbit

Lacrimal ducts

Lacrimal canaliculi

Lacrimal sac

Nasolacrimal duct

Eyes blink, & come together L M, film of fluid over

cornea. This collects together in lacrimal lake which is

drained into canaliculi, then into sac. Nasolacrimal duct to inferior meatus of nasal cavity

Eye ball: 3 coverings

The fibrous coast – sclera & cornea

o Thick outer protective layer

o Sclera: white of eye tough & opaque shape & resistance, attachment of muscle

o Cornea: transparent & anteriorly places

Vascular coat: choroid, ciliary body, iris

o Choroid brown pigmented vascular layer

o Ciliary body: muscular & vascular, contains folds: ciliary processes secreting aqueous

humor, provides attachment to lens. Ciliary muscle contraction & relaxation controls

the thickness of the lens.

o Iris – anterior to lens acts as a central aperture – pupil for light transmission, 2

muscles control size of the pupil

Sphincter papillae – closes (parasympathetic)

Dilator papillae – opens (sympathetic)

Inner coat: retina

o Neural layer – light reception

o Non-visual part – continuation anteriorly, junction between the two is the ora

serrata.

o Fundus: posterior part of retina

Circular depression – optic disc where the optic nerve enters the eye it’s a

blindspot as no receptors.

Macula lutea (just lateral to the disc) has special photoreceptor cones for

acuity; centre of it is the fovea centralis.

Eye ball has anterior & posterior chambers. Anterior between cornea & iris, whereas the posterior

between iris & lens. Both contain aqueous humour produced by ciliary body & drains out into canal

of Schlemm of sclera.

The vitreous body contains transparent gel, between lens & retina & transmits light.

Tarsal glands – the eyelids are strengthened by tarsal plates (dense bands of CT) that contain tarsal

gland, the secretion lubricates the edges of the eyelids & presents them from sticking together

Clinical consideration

Blow out fracture: medial wall & floor of orbit are thin; fractures occur due to blunt trauma, increase

pressure on orbital structures & eyeball causes haemorrhage, medial wall – related to ethmoid

sinuses & floor is related to maxillary sinus.

The red eye: common causes – conjunctivitis, iritis, acute glaucoma, foreign body, corneal abrasion,

corneal ulcer & sub-conjuctival haemorrhage.

Conjunctivitis – bacterial, viral or allergic, burning, itching, gritty eyes, purulent discharge in

bacterial.

Sub-conjuctival haemorrhage – hypertension, trauma, raised intra-abdominal pressure, bleeding

disorder, idiopathic.

Glaucoma – group of disease due to raised intra-ocular pressure (causing compression)

Acute closed angle glaucoma: pain, nausea, reduced vision, photophobia, cloudy cornea, mid-dilated

pupil.

Aqueous humour form posterior chamber travels to anterior chamber

Normally re-absorbed into canal of Schlemm (venous drainage) around the edge of cornea

Any cause of obstruction leads to acute closed angle glaucoma ↑ intra-ocular pressure.

Corneal ulcer – trauma, contact lens, infection, red eye, & ulcer stains with fluoroscein, aggressive

antibiotic therapy, corneal grafting if required. Injury to ophthalmic nerve (V3) loss of sensation to

the cornea so renders it vulnerable by particles

Cataract – opacity of lens – clouding, interferes with vision, lens appear whitish iris shadow is

absent, hand movement perception only. During old age, the lens becomes harder & more flattened

& theses changes slowly reduce their focusing capacity (presbyopia). Some elderly people develop

partial or complete opacity of the lens (cataract)

Sty - is a painful swelling formed when the ducts of the ciliary glands (large sebaceous glands)

become obstructed.

Meibomian cyst – is due to a blocked tarsal gland which lies just posterior to eyelash within the lids.

Facial nerve injury – may result in paralysis of the orbicularis oculi muscle. This prevents the eyelids

form closing fully & loss of protective blinking of the eye As a consequence; the cornea becomes dry

& is left unprotected from dust. Irritation of the eyeball results in excessive tear formation.

Extra-ocular muscles six muscle –superior rectus, inferior rectus, medial rectus, lateral rectus,

superior oblique & inferior oblique & 1 for lifting the upper eyelid levator palpabrae superoris

All 6 muscles, SR, IR, MR, IO – CN III

LR – CN VI (abducens nerve)

SO – CN IV (trochlear nerve)

Optic nerve (CN II) – vision

Oculomotor nerve (CN III) – eye movement

(SR/IR/MR/IO)

Trochlear nerve (CN IV) – SO

Abducens nerve – (CN VI) – LR

Ophthalmic division of trigeminal nerve (v1) – its

branches supply sensation to orbit, eyelids,

forehead & eyeball

The recti muscles arise from a fibrous cuff, the common

tendineus ring that surrounds the optic canal & attaches

to the sclera on the anterior half of the eyeball. The

oblique muscles work synergistically with the recti.

Arteries ophthalmic artery from internal carotid & central artery of retina is a branch of

ophthalmic that pierces optic nerve & emerges at disc.

Veins Ophthalmic veins that drain into the cavernous sinus within cranial cavity.

Clinical

Nerve palsies of CN III, IV, VI paralysis of muscles supplied. Some limitation of ocular movement

causing diplopia (double vision) on using the muscle

CN III: Paralysis of most ocular muscles ptosis, eyeball is abducted & depressed due to

unopposed action of LR & SO

CN VI: paralysis of lateral rectus unable to abduct the eye

Central retinal artery is a terminal branch, near obstruction in any of its branches by an embolus can

result in near total blindness in the effected area.

Thrombophlebitis (vein inflammation) – The facial vein has connection with the cavernous sinus (a

venous channel of the dura mater covering the brain) through the ophthalmic vein. Usually the

blood in the facial vein drains inferiorly but because the facial vein has no valves, blood may pass in

the opposite direction & may enter the cavernous sinus. In patients with thrombophlebitis of the

facial vein, inflammation with secondary thrombus formation, blood clots may pass into the

intracranial venous system.

Lens

Elastic lens fibres, in a capsule, attached to ciliary process, ciliary muscle contraction can cause

tension & relaxation of the lens, circular fibres causing bulging & radial fibres – flattening.

Myopia – light focussed in front of retina short sighted

Hypermetropia – light focused behind the retina long sightedness.

Extra: common disorders of the eye

Major symptoms: loss of vision, eye pain, diplopia (double vision), tearing or dryness of the eyes,

discharge & eye redness

Sudden painless loss of vision may result from retinal vascular occlusion (due to emboli of the

central artery of the retina) or retinal detachment. Gradual painless loss of vision is commonly seen

in chronic simple glaucoma. During embryonic development, the layers of the retina are separated

& fuse during the foetal period. Although the pigmented layer is firmly fixed with the choroid, its

attachment to the neural layer is not firm. Following a blow to the eye, the two layers can separate

(retinal detachment)

Sensation of a foreign body in the eye? Pain in the eye while blinking is seen in corneal abrasions

with the presence of foreign bodies in the eye. Inflammations of the cornea are associated with

significant pain because the cornea has a rich nerve supply. Pain on motion of the eye is seen in

optic neuritis. Eye pain associated with brow or temporal pain may be an indication of temporal

arteritis (AKA cranial arteritis)

Excessive tearing or dryness of the eyes is a common complaint. Abnormal tearing may be caused

either by overproduction of tears or by obstruction of outflow. Dryness results from faulty secretion

by the lacrimal or accessory tear glands.

A watery or mucoid discharge is often associated with allergic or viral conditions, whereas purulent

discharge is associated with bacterial.

Bloodshot eyes: this may result from trauma, infection, allergy or increased pressure in the eye.

Severe coughing spells or recurrent vomiting may cause a patient to have a conjunctival

haemorrhage. A family member with viral conjunctivitis maybe the source

Papilloedema: since the optic nerve is surrounded by meninges with CSF in the subarachnoid space,

increase in the CSF pressure may compress the optic disc. This in turn compresses the blood vessels

supplying the retina, the vein being occluded before the artery. Slow venous return causes oedema

of the eye. The normally depressed optic disc forms a papilla (Papilloedema). This is easily seen

during opthalmoscopy. Continued compression of the optic nerve may lead to visual imparity

Palpebral fissure – the distance between the upper & lower eyelids. Marked ptosis & narrowed

Palpebral fissure may be due to muscle weakness disorder.

Anisocoria – inequality in papillary size may be an indication of neurologic disease.

Mydriasis – pupillary enlargement. It is associated with sympathomimetic agents, glaucoma or

dilating drops.

Miosis – pupillary constriction ids seen with parasympathomimetic drugs, inflammation of the iris &

drug treatment for glaucoma.

Epiphora – tearing of the lacrimal apparatus. If it is present, there may be some obstruction to flow

through the punctum.

Hyphema – haemorrhage within the anterior chamber of the eyeball usually results from blunt

trauma to the eyeball.

Session 3 – The Ear The external ear consists of the auricle & external acoustic meatus (EAC). The former collects sound

whilst the latter leads inward through the tympanic part of the temporal bone & terminates at the

fibrous tympanic membrane.

External ear made up of auricle & external auditory canal. Auricle acts as a funnel which collects

sounds. EAC acts as tubing passing the sound down the canal to the tympanic membrane.

Auricle is made up mainly of elastic cartilage covered with a layer of skin. Arranged in the form of

curved ridges from the helix inwards

Even though mainly elastic cartilage the lobule is made up of fat

Always examine the ear from front, sides, behind & inside & compare to both sides.

Pinna deformities – fix with either trimming the cartilage down, use cartilage from the other ear,

skin tags are harmless but may need removing. Microtia & anotia are associated with middle ear &

EAC abnormalities so they need examination, hearing tests & may need a BAHA with prosthesis.

Pinna Haematoma – occurs between the cartilages of perichondrium preventing in oxygenation

causing pressure necrosis. Common in trauma, later of blood needle evacuation can be down under

local or with know. Needle aspiration, if organised haematoma then formal I&D maybe needed.

With a tight pressure bandage around the outside. Can result in cauliflower ear.

EAM –2.5 cm long, sigmoid goes anterior then medial then down. Examination: pull lateral, posterior

& up. Goes to fibrous tympanic membrane (in kids down & back). Lateral 1/3 is cartilage & inner 2/3

is bony in temporal bone. Lined with stratified squamous epithelium. Contains ceruminous glands

which secrete cerumen which is modified sebum with anti-bacterial properties.

Commonest problem in EAC is a foreign body (cotton bud).

A condition affecting the EAC – the wax is made from cerumen & discarded cells. Some people get

more wax than others. Attempt simple measures to remove it like olive oil & sodium bicarb

Removal with either microsuction or instruments you can use a jobson hall or a wax hook.

Infection of skin of EAC: Complain or discharge, pain & tragal tenderness swimmers, diabetics &

psoriasis suffers. Treated with analgesia, aural toilet, top steroids, & pope wick & water precautions,

caused by pseudomonas

Middle Ear The petromastoid part of the temporal bone contains the middle & inner ears. Its upper surface

forms part of the floor of the middle & posterior cranial fossae. The part forming the front of the

posterior cranial fossae is pierced by the IAM transmitting the facial & Vestibulocochlear nerves. The

inferior surface is irregular & contains the carotid canal for the ICA.

Made up of tympanic membrane, ossicles, muscles, & Eustachian tube & mastoid air cells. It is an air

filled space which through vibrations is transmitted by a chain of ossicles. All held with the pterous

part of the temporal bone.

TM is a shallow concave cone, about 1cm in width, which is angled medially with a 55 deg tilt. The

handle of the malleus is continuous with its posterior aspect. This is a translucent sheet which allows

you to visualise parts of the middle ear especially the malleus. Made up of separated parts. The

tensa contains radially spreading collagen fibres therefore has lots of integral strength but the flacida

has collagen laid down randomly & elastic fibres.

Tympanic perforation can occur. Perforations may be traumatic or secondary to infection. (pressure

necrosis)

Malleus & incus form 1st arch & stapes from 2nd. They relay vibrations from the TM & modify sound

so they concentrate sound energy (amplify it 20 times). The malleus connected to the TM & stapes

to the oval window which is the transmission point to the inner ear. The handle of the malleus &

long process of the incus are parallel to each other. They move down an AP plane.

The muscles act as shock absorbers to dampen any loud sound to protect the inner ear. Tensor

tympani – canal to handle of malleus CN V & stapedius – posterior wall to the neck of stapes CN VII

(facial)

Eustachian tube dysfunction leads to a negative pressure in the middle ear cavity. Part of the upper

RT allows equalisation of pressures from the middle ear & the atmosphere. Allows for efficient

sound energy transfer. The lateral 1/3 is bony in pterous part of temporal bone & medial 2/3 is

cartilaginous. The palatal muscles are attached to the base of the tube & their contraction when

swallowing occurs open the tube causing equalisation of pressure.

The Eustachian tube is usually closed, being intermittently opened by the pull of attached palate

muscles when swallowing.

When the Eustachian tube is blocked the tympanic membrane may be retracted as this occurs in any

condition where intratympanic cavity pressures are reduced. Bulging of the membrane may indicate

fluid or pus in the middle ear.

In infants the tube is wider, shorter & more horizontal also at the tubal end the tubal tonsils are

present until adolescence.

Negative middle ear pressure leads to retraction of the ear drum called tympanic retraction.

Acute otitis media – acute bacterial infection of the middle ear cavity leads to painful, bulging, red

ear drum with pus in the middle ear, & occasionally a perforation & discharge. Complications

include, chronic, facial nerve palsy, acute mastoiditis, perforation, SN hearing loss, labrinthitis,

meningitis & a cerebral abscess.

Caused by – pneumococcus, haemophilus, streptococcus & staphylococcus.

Facial nerve palsy occurs because the nerve lies in the facial canal separated from the middle ear

cavity by a very thin bony partition. So infection can readily cause a lesion of the facial nerve.

More common in children because of immature immunity & anatomical differences

The mastoid process is a large palpable landmark to which several muscles are attached. The cavity

of the mastoid antrum is prolonged into the process by intercommunicating air cells. Middle ear

disease spreads by this route to cause mastoiditis. Mastoiditis infections of the mastoid antrum &

mastoid cells result from a middle ear infection that causes inflammation of the mastoid process.

Infections may spread superiorly into the middle cranial fossa through the petrosquamous fissure in

children & cause Osteomyelitis of the tegmen tympani (a big lump posterior to the ear)

Acute mastoiditis & acute otitis media, can lead to intracranial infection, brain abscesses,

cholesteatoma & meningitis & death. Mastoid air cells area that acts as a reservoir to allow for rapid

aeration. Opening via the mastoid antrum from adults. Don’t exist in infancy & may persist in up to

20% of adults. The layer of bone separating the posterior cranial fossa maybe thin or deficient thus

increasing risk of thrombosis or abscesses

Glue ear – Is otitis media with effusion- thick effusions accumulate behind ear drum, secondary to

prolonged negative pressure. Results in conductive hearing loss. This can lead to speech

impediment, failing at school. Risks smoking, bottle fed, day care, cleft palate, Treat with watchful

waiting, hearing air or grommits.

Grommet’s are ventilation tubes that equalise the middle ear pressure.

Cholesteatoma – negative middle ear pressure retraction pockets dead skin cells accumulate

in pockets necrotic mass of dead skin (cholesteatoma) erosion of middle ear structures & bone

via lytic enzymes.

It is nasty disease which is hard to diagnose. Associated with OM with mucopurulent DC, hearing

loss, CN VII palsy & vertigo

Always examine the pars flacida crusts in this region can hide a cholesteatoma

Complications of middle ear disease facial nerve dysfunction – the facial nerve runs through the

middle ear & is vulnerable to damage from disease, the chorda tympani can also be affected.

Internal Ear

Made up of the cochlea & vestibular labyrinth

The internal ear consists of a series of bony cavities (the bony labyrinth) & membranous ducts & sacs

(the membranous labyrinth) within these cavities. All these structures are in the pterous part of the

temporal bone between the middle ear laterally & the internal acoustic meatus medially.

The membranous labyrinth contains fluid called the endolymph. A fluid called perilymph separates

the bony & membranous labyrinths. The labyrinth contains the vestibule, semicircular ducts &

canals, cochlea & the spiral organ of corti.

The cochlea is the organ for sound transduction – coiled helical structure which is encased in hard

bone of the pterous part of the temporal bone. When it is anatomically represented it is tonotopic

that means that different areas are frequency specific. High frequencies are at the base & low

frequencies are at the apex. The organ of corti is the end point as its hair cells innervated by the

cochlea nerve which converts movement into what we perceive as sound.

The vestibular system functions to provide information about angular & linear acceleration, 5

separate neuroepithelial elements – the 3 Semicircular Canals, the utricle & the saccule. Paired

canals give complimentary information about direction.

Cochlea disease age related degradation, noise induced, ototoxic, tests – audiology, radiology.

Vestibular disease – four main symptom complexes present with true rotational vertigo – diagnosed

on the history of the vertiginous attacks.

Timing

Secs to Mins - Benign Paroxysmal or Positional Vertigo

Mins to Hours - Meniere’s Disease

More than 24hrs - Labyrinthine Failure

Random & with other symptoms - Vertiginous Migraine

Benign positional paroxysmal vertigo – vertigo typically lasts seconds due to otolith displacement

Meniere’s disease – due to endolymphatic hydrops

Other causes of VERTIGO – vascular, epilepsy, receiving treatment, (tumours, trauma, thyroid),

infections, glial (MS), ocular.

Extra: common disorders of the ear

External otitis & otitis media are very common causes of otalgia. Pain from the teeth, pharynx &

cervical spine is commonly referred to the ear. Inflammation, trauma, or neoplasms anywhere along

the course of the trigeminal, facial, glossopharyngeal & vagus nerves or C2 & C3 may be responsible

for referred pain to the ipsilateral (same side) ear

Pruritis (itching) of the ear may result from primary disorder of the external ear or from a discharge

from the middle ear.

Otorrhoea (discharge from ear) generally indicated acute or chronic infection. A blood discharge may

be associated with leakage of CSF associated with skull fracture.

The external auditory canal is also exposed to trauma, infections, such as otitis externa, & growths

like exostosis (growth of new bone) involving its bony part.

Typanosclerosis – is the term to describe the secondary healing leading to scar tissue after a

tympanic membrane has become perforated.

An interference with sound conduction in external or middle ear, leads to conductive deafness while

a disorder/disease involving the inner ear or neuronal structures leads to sensorineural deafness.

Inner ear disorders can cause vertigo which leads to disorders of balance & equilibrium.

When some people clear their ears with a cotton bud they cough or even vomit. This is due to the

nerve supply of the auditory canal & tympanic membrane is via an auricular branch of the vagus

nerve. This nerve may also carry Glossopharyngeal & facial nerve fibres & some people who are

particularly sensitive to stimulation of these nerves may well develop an ear-cough reflex or

occasional vomiting which may be associated with vagal & Glossopharyngeal innervations.

Session 4 – Nose Functions: olfaction/smell, respiration (filters & humidifies), receives local secretions (sinuses,

Nasolacrimal duct, cosmetic, & involved in speech

Skeleton – nasal bones, frontal processes of maxillae, nasal part of frontal bone & the bony nasal

septum. The cartilaginous part

consists of 5 cartilages.

External nose

Blood supply: anastomoses of

branches from the facial artery

(from ECA) & ophthalmic from ICA

Veins – facial vein into internal

jugular & ophthalmic into

cavernous sinus.

Nerve supply via the trigeminal

nerve CN V & V1 & V2 branches

Nasal fracture

Mechanism of injury –

direct blow on the nose may result in fracture of the cribriform plate of the ethmoid bone

resulting in tearing of the overlying meninges & leakage of CSF into nasal cavity.

Epistaxis

Nasal obstruction

Will find:

o Bony tenderness; Deviation; Lacerations; Haematoma; CSF rhinorrhea; Raccoon eyes

Nasal Cavity Septal bones: ethmoid [perpendicular plate], vomer & septal cartilage

Floor is made from the maxilla (palatine plate), palatine (horizontal plate) & the posterior nares

Nasal roof bones are made from the frontonasal, ethmoid (crista galli, cribriform plate) the sphenoid

(opening of the sphenoidal sinus)

Nasal septum – mucosa, perichondrium (or periosteum), hyaline cartilage (type 2 collagen) or bone

Lateral walls – vestibule, atrium, Eustachian tube, spheno-ethmoidal recess & the turbinates:

Superior concha or superior meatus

Middle concha – middle meatus

Inferior concha – inferior meatus

The mucous membrane lining of the turbinates is highly vascular for the purpose of humidifying the

inspired air.

The area between the superior turbinate & the cribriform plate is called the sphenoethmoidal

recess. The lining epithelium of the mucous membrane in this region is modified for the purpose of

olfaction; axonal process of the olfactory cells pass through the plate & penetrate the meninges

before entering the olfactory bulb.

Arteries to the septum only – greater palatine (maxillary – ECA) & superior labial (facial – ECA)

Septum & lateral – sphenopalatine (maxillary – ECA), posterior ethmoidal (ophthalmic – ICA) &

anterior ethmoidal (ophthalmic – ICA)

Olfactory nerve fibres – pseudostratifed columnar epithelium receptors located on cilia of receptor

cells (1000 classes). One cell-one type of receptor – one odour

Bulb – located superior to cribriform plate at frontal lobe base, complex processing centre, revives

receptor cell axons. Olfactory tract projects to olfactory cortex – frontal lobe, temporal lobe,

thalamus, & hypothalamus.

Septal deviation can be either congenital or traumatic; C-shaped or S- shape & to fix it is called a

septoplasty.

Septal haematoma – immediate drainage required to stop septal necrosis saddle deformity,

manipulation at 10 days is required.

Septal perforation Aetiology:

Iatrogenic

Trauma

Nose picking

Cocaine

Malignancy

Whistling

Crusting

Epistaxis

Nasal collapse

Rhinitis inflammation of the nasal mucosa – symptom complex – sneezing, congestion, itching,

rhinorrhea

Allergic – type 1 IgE hypersensitivity

Infectious

Non-allergic rhinitis

o Eosinophilic; NARES, polyposis

o Non-eosinophilic; vasomotor, atrophic, drug-induced, hormonal, exercise, gustatory,

inflammatory

Structural/mechanical factors – septal deviation, turbinate hypertrophy, adenoid

hypertrophy, foreign body, tumour

Management – avoid irritants, immunotherapy, surgical

Or medical ways – douching, nasal steroids & anticholinergics, decongestants, antihistamines,

leukotriene receptor antagonists

Infections of the nasal cavity may spread to the anterior cranial fossa through the cribriform plate of

the ethmoid bone, into the paranasal sinuses via their openings into the cavity & to the lacrimal

apparatus & conjunctiva via the opening of the Nasolacrimal duct. The middle ear may become

infected via the Eustachian tube.

Epistaxis – acute haemorrhage from nostril, nasal cavity or nasopharynx occurs in 1 in 7 people. In

the 2- 10’s & the 50+ years

Anterior (90%): Little’s area Posterior (10%): sphenopalatine

Arteries affected greater palatine, sphenopalatine, anterior & posterior ethmoidal, superior labial.

Local causes – idiopathic, dry & cold weather, traumatic, inflammatory, neoplastic

Systemic causes – HT, abnormal coagulation, CT diseases

Treatment ladder – ABC, RICE, correction of BP & clotting, vasoconstrictors & cauterisation

Later treatment – packing, submucosal resection, embolisation ECA & branches, ligation of vessels

Olfactory disorders

1% of population <60 years, 50% of population > 60 years

Anosmia – absence of small sensation

o can be due to fracture of the cribriform plate

Partial Anosmia – ability to perceive some odours

Hyposmia: decreased sensitivity to odours.

Hyperosmia – abnormally acute smell function

Dysosmia: distorted smell perception

Phantosmia: olfactory hallucination

Olfactory agnosia: inability to recognise an odour.

Causes:

Conductive loss – obstruction of nasal passages from inflammation, septal deviation,

polyposis

Sensoineural loss – damage to neuroepithelium – viral infection, neoplasm, airborne toxin,

radiotherapy.

Central olfactory neural loss – CNS damage – trauma, tumours, neurodegenerative

disorders, congenital.

History – smell before loss, loss of taste, antecendent events, severity, onset, other medical Hx, nasal

sinus disease, medications, smoking Hx, occupational Hx.

Examination – ENT, nasendoscopy, neurology, CT, nasal & sinus disease & MRI for intracranial causes

Then a smell test with microencapsulated odours.

Benign masses in the nasal cavity – polypi (which originate from the sinuses) rhioliths (stone

formation or foreign bodies.

Tumours & invasive infections (like fungal) can spread to the cranial cavity

Sinuses

Paranasal sinuses – air filled extensions to respiratory part of nasal cavity 4 paired sinuses:

Frontal – 8 years – 12 (when they are formed)

Maxillary – birth to 3 years

Ethmoidal – birth to 3

Sphenoidal – 3 -12

Functions:

Extension of nasal cavity – humidification & warming of air

Lightening weight of skull

Buffer for trauma

Regulation of intranasal pressure

Insulating sensitive structures from temperature variations – dental roots, eyes

Secretion of mucus to moisten nasal chambers

Increasing resonance of the voice

Frontal sinuses- pyramidal 6-7mL, between outer & inner tables of frontal bone – pneumatisation

Asymmetrical & variable

Relations –

o posterior – frontal lobe/anterior cranial fossa

o Floor – orbit

Nerves – branches of CN V1

Blood from branches of ophthalmic artery – ICA

Maxillary sinuses – largest 15 – 30 mL

Drainage reliant on cilia, its in the body of the maxilla:

Floor – alveolar maxilla, roots of premolar & molar teeth

Roof – orbital floor, infraorbital nerve

Posterior – pterygopalatine fossa, maxillary artery.

Nerves- branches of CN V2 Blood – maxillary artery branches

Ethmoid sinuses – labyrinth of around 20 communicating air cells on the superolateral nasal wall:

Roof – cribriform plate, anterior cranial fossa

Lateral – lamina papyracea, orbits

Posterosuperior – orbital apex, optic nerve

Nerves – branches of CN V1 & orbital branches of sphenoplatatine ganglion, Blood- ophthalmic

Sphenoid sinuses – in the body of the sphenoid bone – 7.5 mL small at birth:

Lateral – cavernous sinus CN 3 – 4, ICA

Roof – pituitary =, optic nerves & chiasm

Posterior – pons

Nerves- branches of CN V1 Blood – branches of ophthalmic (ICA) & sphenopalatine ECA

Sinusitis

Obstruction of natural ostia (opening)

Hypooxygenation

Ciliary dysfunction & poor mucous quality

Retention of secretions

Local factors - cold air ‘stuns’ the epithelium & dry air dessicates the blanket

Anatomical factors – polyps, tumours, foreign bodies, rhinitis – block the ostia

Kartagener’s syndrome – immotile cilia.

Acute - < 1 month Subacute – 1- 3 months Recurrent acute - >4 episodes/yr

Organisms – viral, streptococcus pneumoniae, S. aureus, H. influenzae, P. aeruginosa, fungal

Aetiology – acute infective rhinitis, dental, fractures, swimming, nasal obstruction, neighbouring

infection.

Features – pain & tenderness in face, headache, nasal discharge, systemic upset

Differential – toothache, migraine, neoplasm, trigeminal neuralgia, TMJ pain

Treatment – analgesia, steam inhalations, antibiotics, decongestants, drainage, avoid cigarettes &

alcohol.

Complications

Intracranial – meningitis, extra-dural abscess, subdural abscess, cavernous sinus

thrombosis, cerebral abscess

Orbital – oedema, cellulitis, subperiosteal abscess, orbital abscess

Osteomyelitis – pott puffy tumour.

Chronic sinusitis > 3 months

Clinical features – post-nasal drip, Anosmia, foul taste, nasal obstruction

Investigations – nasendoscopy, CT sinuses

Treatment – conservative OR surgical, functional endoscopic sinus surgery but risks orbit &

cribriform plate

Nasal Polyposis: M > F & >40 years

90% oedematous eosinophilic polyps – ethmoidal – middle meatus

Antrochoanal – unilateral maxillary

Causes: allergic rhinitis, CF, Kartagener’s syndrome.

Features: rhinorrhea, purulent postnasal drip, nasal obstruction, change in voice, Anosmia, taste

disturbance, mucucoele.

Treatment – steroids – topical or systemic OR polypectomy

Need imaging if suspicion of intracranial extension, often recurrent post-surgery.

Session 5: Development of the Brain & External Features Neural tube forms in week 3 by the end of week 4 the embryo is 3D. The primitive gut tube has

formed.

Early in week 4 there is a face with no distinguishing features, but head & neck represent ½ the

length of the embryo.

The face development is driven by the expansion of the cranial neural tube & the

appearance of a complex tissue system associated with the cranial gut tube & the

outflow of the developing heart. The development of sense organs also impact

development & the need to separate the respiratory tract from the GIT.

Notochord signals cause overlying ectoderm to thicken, slipper-shaped neural plate.

Edges elevate out of the plane of the disk & curl towards each other, creating the neural

tube.

Anterior of neural tube begins to form the brain. 3 vesicle stage – prosencephalon (forebrain- aids

eye formation), mesencephalon (midbrain), rhombencephalon (hindbrain).

Neural crest – a specialised population of cells that originates within the neurectoderm (could be

called the 4th germ linage). Cells of the lateral border of the neurectoderm become displaced & enter

the mesoderm & migrate & contribute to a variety of H&N structures.

Branchial/fes – external appearance begins to change arches & clefts appear in the upper neck

region. Pharyngeal arches are arranged around aortic arch vessels. Each arch has:

Artery (aortic arch), vein & cranial nerve

Mesenchyme ‘filling’

Ectodermal covering

Endodermal lining.

Facial skeleton – neural crest of 1st pharyngeal arch

Muscles of mastication – mesoderm of 1st pharyngeal arch

Muscles of facial expression – mesoderm of 2nd pharyngeal arch

Facial Primordia – 1st pharyngeal arch, frontonasal prominence formed –surrounds ventro-lateral

part of the forebrain & the Primordia of the eyes.

Stomatodeum – is a depression between the brain & the pericardium in an embryo, & is the

precursor of the mouth & the anterior lobe of the pituitary gland.

Frontonasal prominence – makes the forehead, bridge of nose, nose & Philtrum formed from

mesenchyme near the brain

Maxillary prominence (1st pharyngeal arch) – cheeks, lateral upper lip & later upper jaw

Mandibular prominence (1st pharyngeal arch) – lower lip & jaw

NOSE

Nasal placodes appear on the FNP 5 week, & then sink to become the nasal pits, medial & lateral

nasal prominences form on either side of the pits.

Placodes are thickening of ectoderm where you have a sensory organ being created

Maxillary prominences grow medially, pushing the nasal prominences closer together in the midline.

Then fuse with medial nasal prominences, these then fuse in the midline. This places the eyes

anteriorly.

Fusion of the medial nasal prominences creates the intermaxillary segment:

Labial component – Philtrum

Upper jaw – 4 incisors

Palate: primary palate

Main part of definitive palate is secondary palate derived from palatal shelves derived from maxillary

prominences.

Maxillary prominence gives rise to two palatal shelves; these grow vertically downwards into the

oral cavity on each side of the developing tongue. Mandible grows large enough to allow the tongue

to drop, the palatal shelves then grow towards each other & fuse in the midline. The nasal septum

develops as a midline down-growth & ultimately fuses with palatal shelves.

Lateral cleft lip – failure of fusion of medial nasal prominence & maxillary prominence

Cleft lip & cleft palate – combined with failure of palatal shelves to meet in midline (& above)

Fates of the facial prominences

Frontonasal Forehead, bridge of nose, medial & lateral nasal prominences Medial nasal Philtrum, primary palate, mid upper jaw Lateral nasal Sides of the nose Maxillary Cheeks, lateral upper lip secondary palate, lateral upper jaw Mandibular Lower jaw & lip.

Eyes

Development begins the 4th week, out-pocketings of forebrain these grow out to make contact with

the overlying ectoderm, forming optic placodes lens

Optic vesicle grows out toward surface to make contact with lens placodes this then invaginates &

pinches off.

Eye Primordia are positioned on the side of the head, as facial prominences grow, the eyes move to

the front of the face forming binocular vision.

External ear

External auditory meatus develops from 1st pharyngeal cleft auricles develop from proliferations

within 1st & 2nd pharyngeal arches surrounding the meatus.

External ears develop initially in the neck but as mandible grows the ears ascend to the side of the

head to lie in line with the eyes all common chromosomal abnormalities have associated external

ear anomalies.

Foetal alcohol syndrome – pharyngeal there is no known safe level of alcohol consumption during

pregnancy, neural crest migration as well as development of the brain are known to be extremely

sensitive to alcohol, Incidence of foetal alcohol syndrome & alcohol related neural development

delay = 1/100 births. It affects glucose metabolism.

The Pharyngeal arches & their derivatives

Pharyngeal arches

A system of mesenchymal proliferations in the neck region of the embryo, 5 in total, numbered 1 to

6 (5th does not form in humans)

The facial skeleton is derived from the frontonasal prominence & the 1st pharyngeal arch & also

forms the muscles of mastication. The muscles of facial expression are ph Arch 2 derivatives

3rd arch = stylopharyngeus

4th arch – circothyroid, levator palatine, constrictors of the pharynx

6th arch – intrinsic muscles of the larynx

All except CN 1 & 2 are derived from mid or hind brain, CN 1 & 2 are from forebrain.

Nerves of the pharyngeal arches

CN V, CN VII, CN IX & X

Mixed sensory & motor functions they all supply the derivatives of the pharyngeal arches

CN XI & CN XII have relationship with pharyngeal arch system

CN V – trigeminal nerve – the nerve of the 1st arch

CN VII – facial nerve – nerve of 2nd arch

CN IX – Glossopharyngeal nerve – nerve of the third arch

CN X – nerve of the 4th & 6th arches, 4th arch branch is superior laryngeal nerve (supplies circothyroid

& constrictors of the pharynx). 6th arch branch is the recurrent laryngeal nerve – supplies intrinsic

muscles of the larynx.

Cartilages of the pharyngeal arches

1st arch cartilage: Meckel’s 1st arch divides into maxillary & a mandibular prominence, mandibular

prominence develops from prominent Meckel’s cartilage forms the malleus & incus & provides

template for mandible which forms by membranous ossification.

2nd arch cartilage: Reichert’s also contributes to inner ear – stapes. Also styloid process & hyoid

bone (just the lesser cornu & upper body)

Epiglottis – 4th & 6th arch mesenchyme (pharyngeal floor)

Thyroid, arytenoids, cricoids all form from the 4th & 6th cartilage bars

The aortic arches

Aortic sac lies in floor of the pharynx

1st & 2nd arches lie in floor of the pharynx

1st & 2nd arch arteries disappear

3rd arch artery – internal carotid

4th arch artery – arch of aorta & brachiocephalic A

6th arch artery – pulmonary arch

The pharyngeal pouches

These are out-pocketings of the primitive gut tube in the pharynx. There are 4 pouches, each giving

rise to glandular structures in the H&N. Some pouch-derivatives undergo extensive migration from

point of origin.

External ear is derived form 1st & 2nd pharyngeal arch proliferations, cleft between becomes the

meatus. But

Middle ear – the ossicles – cartilage bar derivatives

Tympanic cavity & auditory tube – 1st pharyngeal pouch derivatives

Inner ear – otic placodes (extensive contributions from multiple areas), invaginate to form auditory

vesicles & the membranous labyrinth.

Parathyroids, thymus an tonsils

2nd pouch epithelial proliferation, followed by colonisation by lymphoid precursors

3rd & 4th pouch divide into dorsal & ventral components

3 & 4 dorsal make the parathyroid & the 3 ventral makes the thymus.

Pharyngeal clefts

1st cleft is all that remains & 2nd arch grows down to cover others, obliterating all other clefts. But

there can be remnants...

Branchial cysts & fistulae – if the cervical sinus is not obliterated, cysts or fistulae can occur, these

can occur anywhere along the anterior border of SCM (2nd, 3rd & 4th pharyngeal clefts)

Summary

Ph. arch Nerve Muscles Skeleton

1st V trigeminal of mastication, digastrics, mylohyoid

Meckel’s cartilage – mandible malleus & incus

2nd VII Facial of facial expression Reichert’s cartilage – stapes, some of hyoid & lesser horn, styloid process, stylohyoid ligament

3rd IX glossopharyngeal Stylopharyngeus lower body & greater horn of hyoid 4th X superior laryngeal

branch Pharyngeal muscles, cricothyroid

Thyroid cartilage, cricothyroid cartilage

6th X recurrent laryngeal branch

Intrinsic muscles of larynx

arytenoid cartilage

The tongue, pituitary & thyroid glands

The pituitary gland

The pituitary has ectoderm & neurectoderm origins. Downward out-growth of the forebrain which

grows towards the roof of the pharynx. A down growth from the diencephalon forms inn the

midline. It is called the infundibulum. It always retains connection with the brain. The part of the

diencephalon from which it arises becomes the floor of the hypothalamus. The connection becomes

the pituitary stalk. Nerve fibres tracts develop in the stalk, growing down from the hypothalamus.

Rathke’S POUCH is an out-pocketing of ectoderm of the Stomatodeum. An evagination of the roof of

the oropharnyx which grows dorsally towards the developing forebrain. It loses its connection with

the roof of the mouth & comes to lie anterior to the infundibulum & wrap around the pituitary stalk.

The cells of Rathke’s pouch differentiate into the endocrine cells. Persistent remnants of RP may

form cysts.

The tongue

Primordia of the tongue appear at about the same time as the palate begins to form, receives a

component from each of the pharyngeal arches.

Derived from 2 lateral lingual swelling (arch 1) & 3 median lingual swellings (arch 1 tuberculum

impar) arch 2 & 3 (cupola) & arch 4 gives rise to the epiglottal swelling

Lateral lingual swellings over-grow the tuberculum impar. The 3rd arch component of the cupola

over-grows the 2nd arch component. Extensive degeneration occurs, freeing tongue from the floor of

the oral cavity (lingual frenulum).

Sensory innervation

Mucosa of ant. 2/3 is derived from arch 1 & 3. General sensory innervation CN V & IX

Posterior 1/3 derived from A 3 & 4 – general & special sensory CN IX & X

Taste buds develop in papillae – special sensory innervation CN VII

Chorda tympani branch of CN VII from 2nd arch but passed into 1st arch therefore passes through the

middle ear.

Motor innervation – both intrinsic & extrinsic muscles of the tongue develop from myogenic

precursors that migrate into the developing tongue (CN XII)

The Thyroid gland

Primordium of the thyroid gland appears in the floor of the pharynx between the tuberculum impar

& the cupola, final position is anterior neck.

Descent – point of origin for the descent of the thyroid is later marked by the foramen cecum.

Bifurcates & descends as a bi-lobed diverticulum connected by the isthmus. Migrates anterior to the

pharyngeal gut, hyoid bone & laryngeal cartilages.

During its decent the thyroid gland remains connected to the tongue by the thyroglossal duct into

the pyramidal lobe.

Can get thyroglossal cysts (if remnants persist- always midline of neck ) & fistulae, ectopic thyroid

tissue.

Treacher-collins syndrome – characterised by Hypoplasia of mandible & facial bones it is an

inherited, autosomal dominant condition.

Di-George Syndrome – congenital thymic aplasia & absence of parathyroid glands deletion on

chromosome 22 abnormal development of neural crest & congenital heart defects.

The Temporomandibular joint The temporal region includes the temporal & infratemporal fossae. The temporal fossa, lying on the

lateral aspect of the skull, comprises the temporalis muscles & its neurovascular supply structures.

The infratemporal fossa which lies beneath the base of the skull between the pharynx & the ramus

of the mandible, contains some muscles of mastication (lateral & medial pterygoids muscles)

branches of the mandibular nerve (V3), maxillary artery, the otic ganglion & chorda tympani (branch

of facial N).

The TMJ is the articulation between the condylar head of the mandible & the mandibular fossa of

the temporal bone. It is a modified synovial joint whose movements are mainly by the muscles of

mastication

Nerve blocks: dentists commonly produce inferior alveolar nerve block. The anaesthetic is injected

around the mandibular foramen (inferior alveolar nerve & vessels pass through here) on the medical

side of the mandible to anesthetise all mandibular teeth on that side.

Dislocation of TMJ can be due to yarning or taking a large bite, excessive contraction of the lateral

pterygoids may cause the heads of the mandible to dislocate anteriorly (pass anteriorly to the

articular tubercles). In this position the mandible remains depressed & the person is unable to close

their mouth. More commonly a sideways blow to an open mouth can cause this. Posterior

dislocation is uncommon, because being resisted by the presence of the postglenoid tubercle & the

strong intrinsic lateral ligament caused by direct blows to the chin.

Fractures of the mandible may be accompanied by dislocation of the TMJ. The close relationship of

the auriculotemporal nerve (branch from V3) to the joint makes it vulnerable to injury when there is

a traumatic dislocation of the joint accompanied by tearing of the joint capsule & associated

structures. In such a case, the TMJ becomes lax & unstable.

Pharynx & Larynx Session 7

Nasopharynx - boundaries

Superior – skull base

Inferior – level of the soft palate

Post – nasopharyngeal tonsil

Ant – choanae (posterior nasal apertures)

o Lined with respiratory ciliated

stratified squamous epithelium

Contents nasopharyngeal tonsil (adenoids) – part

of waldeyer’s ring & the Eustachian tube orifice (so if

adenoids are swollen they can block this)

Oropharynx

Behind mouth & tongue

Boundaries:

Superior – level of soft palate

Inferior – superior edge of epiglottis

Post – C2 & C3

Ant – oral cavity

Lined with stratified squamous epithelium.

Contends palatine tonsils & the anterior & posterior tonsillar pillars tonsils are big bits of

lymphoid tissue.

The tonsils lie in tonsillar fossae (between anterior & posterior pillars)

Anterior pillar (palatoglossal arch) which is the boundary between buccal cavity & the oropharynx,

fuses with lateral wall of tongue & contains palatoglossal muscle.

Posterior pillar (palatopharyngeal arch) – blends with wall of pharynx, contains palatopharyngeus

muscle.

The tonsils are encapsulated, the tonsillar fossa floor being the superior constrictor muscle,

lymphoid tissue covered with squamous epithelium. They atrophy after puberty maximal size

between 3 & 8 years old. The lingual tonsil refers collectively to numerous lymphoid nodules on the

posterior 1/3 of the tongue

The blood supply is the facial artery tonsillar branch. Venous drainage into the pharyngeal plexus.

Lymph – pierce superior constrictor muscle; pass to nodes along the IJV, & into the jugulodigastric

node (node up in tonsillitis). (Angle of mandible)

Laryngopharynx

Area below the epiglottis

Boundaries:

Superior – superior edge of epiglottis

Inferior – level of inferior edge of cricoids cartilage

Post – C3 – 6

Ant – larynx

Inferiorly opens into oesophagus & is lined with stratified squamous epithelium

Muscles of pharynx

Superior, middle & inferior constrictor – overlap each other, open anteriorly, attached posteriorly be

median raphe.

Swallowing: pushing food from oral cavity to oropharynx

Tongue & suprahyoid muscles pull up hyoid & larynx up

Soft palate elevates – nasopharynx closed off

Superior constrictors contract

Food bolus passes into laryngopharynx by aid of middle & inferior constrictors.

Larynx protected by – overhanging tongue, epiglottis & vocal cords

Lastly cricopharyngeus relaxes

Blood supply of pharynx

Arterial – superior thyroid artery, ascending pharyngeal artery, ascending & descending palatine

artery, branches of lingual, facial & maxillary arteries. From ECA)

Venous – pharyngeal venous plexus into the IJV

Nerve supply –

Motor – vagus (X), glosopharyngeal (IX), hypoglossal (XII), facial (VII)

Sensory:

Nasopharynx – maxillary division of trigeminal (V2)

Oropharynx – glosopharyngeal (IX)

Hypopharynx - hypoglossal (XII)

Larynx

Functions

Respiration – valves open

Phonation (partially closes valve)

Protecting trachea/ bronchial tree

whilst swallowing

Cough reflex

Supraglottis – inferior surface of epiglottis

to vestibular folds (false cords)

Glottis – vocal cords (including 1 cm

inferiorly)

Subglottis – down to lower border of

cricoids cartilage

Epiglottis – leaf shaped plate of elastic

fibrocartilage

Attached posterior to thyroid cartilage by

thyroepiglottic ligament

Vallecula – depression between tongue

base & epiglottis

Thyroid cartilage – laryngeal prominence (Adam’s apple), largest cartilage comprising of 2 lamina

Superior & inferior thyroid horns (hyoid & cricoids respectively)

Cricoid cartilage – most inferior cartilage, completely encircles the airway, signet ring shape. 2

articular facets on each side:

Superolateral surface for arytenoid cartilage

Lateral surface for the medial surface of inferior horn of thyroid cartilage.

Arytenoid cartilage

Pyramid shape – concave base articulating with cricoid – involved in vocal cord movement.

Vocal Cords Layers:

Stratified squamous epithelium

Reinke’s space

Vocal ligament

Vocalis muscle.

Mucosa – is firmly adherent to the vocal ligament without there being any intervening submucosa.

This accounts for the pearly white avascular appearance of the vocal cords. Absence of intervening

submucosa tissue means that no fluid can collect underneath the vocal cords; thus the vocal cords

do not become oedematous during URTIs

Muscles - abduction – posterior cricoarytenoid Adduction – lateral cricoarytenoid

Laryngeal Blood supply

Arterial – superior laryngeal artery (from superior thyroid artery), inferior laryngeal artery (from

inferior thyroid artery)

Venous – superior laryngeal vein & inferior laryngeal vein.

Laryngeal nerve supply

Superior Laryngeal nerve (branch X) – deep to carotid arteries; internal – pierces thyrohyoid

membrane external – deep to superior thyroid artery, supplying cricothyroid muscle. The muscle is

the only external muscle of the larynx & functions in tensing the vocal cord by its slight tilting action

on the cricoid cartilage.

Recurrent laryngeal nerve (branch X)

Right – under Subclavian artery

Left – under aortic arch

Tracheo-oesophageal groove.

Supplies al laryngeal muscles apart from cricothyroid. In particular innervates the posterior

cricoarytenoid on each side) these rotate the arytenoid cartilages outwards, thus separating

the vocal cords.

Disorders of both

Adenoids – mass of lymphoid tissue, produce IgA, IgG, IgM maximal size 3 – 8 years enlargement

with infection

Effects of enlargement:

Nasal obstruction results in mouth breathing, obscured speech, feeding difficulty, snoring/obstructive sleep apnoea

Eustachian tube obstruction results in recurrent acute otitis media or worse chronic otitis media with effusion (glue ear)

The adenoids are different to assess – done by post-nasal space x-ray, or post-nasal mirror, fibre-

optic endoscope & in theatre.

Obstructive sleep apnoea – spectrum from mild snoring to OSA, partial/complete airway obstruction

during sleep (turbulent airflow), over 30 apnoeic episodes in 7 hours of sleep, 5 apnoeic episodes an

hour. Daytime tiredness, if severe can cause hypoxia & increase CV strain.

Adenoidectomy – either curettage or suction diathermy

Complications- bleeding, atlanto-occipital joint dislocation, Eustachian tube stenosis.

Tonsillectomy

Indications:

Recurrent tonsillitis (5/year for 2 years)

Previous peritonsillar abscess

Suspected cancer

Obstructive sleep apnoea syndrome

Risks – bleeding (tonsillar branch of facial artery or from large external palatine vein), infection, the

CN IX and ICA are also closely related.

Technique – cold steel or electrosurgery.

Pharyngeal pouch:

Posterior herniation of pharyngeal mucosa, occurs through Killian’s dehiscence (between inferior

constrictor & cricopharyngeus muscles)

Reasons – weaker area, in coordination of pharyngeal phase of swallowing. Cricopharyngeal spasm

Recurrent laryngeal nerve palsy

Idiopathic

Laryngeal cancer

Thyroid disease

Trauma

Cervical lymphadenopathy

Oesophageal cancer

Apical lung cancer

Aortic aneurysm

Neuropathic (diabetes

Hypopharyngeal/Laryngeal Carcinoma

Hypopharyngeal - 90% are SCC, uncommon, post-cricoid, piriform fossa, in the posterior pharyngeal

wall.

Laryngeal – 95% are SCC commonest H&N Ca in west, M:F 5:1 , smoking & alcohol, Supraglottis,

glottis (good prognosis), Subglottis (poor)

History:

FB sensation in throat

Dysphagia, odynophagia (pain on swallowing)

Otalgia (referred pain –vagus)

Hoarse voice due to spread to RLN

Couching (aspiration, haemoptysis

Weight loss

Smoking history (pack/years)

Examination – loss of laryngeal crepitus, cervical lymph node metastasis, endoscope

Investigations – barium swallow, CT/MRI, direct pharyngo-laryngo-oespohagoscopy & biopsy.

TNM staging

Management – radiotherapy, maybe chemotherapy, laryngectomy, pharyngo-laryngectomy,

including radical or selective neck dissections, palliation

Thyroid surgery – hemi/sub-total/total thyroidectomy potential for iatrogenic injury to superior

laryngeal & recurrent laryngeal nerves as these accompany the arterial to the thyroid.

Piriform fossae – fish bones may get stuck here. If it is sharp then it may pierce the mucous

membrane and injure the internal laryngeal N. during removal the superior and internal laryngeal

nerves are vulnerable to injury in the mucosa gets pierced.

Session 8 - Lymphatic Drainage of the Head & Neck Organised into a several regional groups & a terminal group. The regional group comprise the

occipital, retroauricular, parotid, buccal, submandibular, submental, anterior cervical, superficial

cervical (along course of EJV), retropharyngeal, laryngeal & tracheal nodes.

The terminal group of nodes or deep cervical nodes receive all the afferent lymph vessels of the H&N

either directly or indirectly, via one of the regional groups. The

terminal group is closely related to the carotid sheath, & in

particular, to the IJV. Two of the nodes the jugulodigastric & the

juguloomohyiod, are important. The jugulodigastric node

(tonsillar node) is located just below & behind the angle of the

mandible & is concerned with the lymph drainage of the tonsil

& the tongue. The juguloomohyiod node is mainly associated

with the lymph drainage of the tongue, oral cavity, trachea,

oesophagus & thyroid

gland.

A few deep cervical nodes

extend into the posterior triangle of the neck & lie along the

course of the accessory nerve affected by a malignancy in the

neck. Nerve may be damaged some nodes in the root of the

neck enlarge in the late stages of malignancies of the thorax &

abdomen.

The efferent lymph vessels from the deep cervical nodes join to

form jugular lymph trunks. On the left side it usually joins the

thoracic duct which enters the left brachiocephalic vein at the junction of the subclavian & IJV. The

right side, it enters the venous system at the junction between the subclavian & IJV via a short right

lymphatic duct.

When cervical metastases occur, the surgeon usually performs a block dissection of the cervical

nodes. This procedure involved the removal en bloc of the IJV, the fascia, the lymph nodes & the

submandibular salivary gland. The aim of the operation is removal of all the lymph tissues on the

affected side of the neck.

Inspection of the head & neck

position of head – see if patient is holding his head erect or not

Is there any asymmetry of the facial structure

Is head in proportion to the body

Any masses are present, their size, consistency & symmetry are recorded

Check scalp for lesions & description of hair

Check neck for symmetry, patient asked to extend the neck. Look for scars & masses

A distended thyroid.

Palpation of the Head & neck

The pads of the fingers should roll the underlying skin over the cranium in circular motion to

assess its contour & to feel for the presence of lymph nodes or masses.

Suggested approach – start with occipital region, posterior auricular of the neck jaw

margin along the jaw area in front of the ear

All nodes felt should be assessed for mobility, consistency & tenderness; the tender lymph

nodes are said to be inflamed, firm & fixed malignancy.

Palpation of the supraclavicular nodes – from the back of the patient place fingers into the medial

supraclavicular fossae, deep to the clavicle & adjacent to the SCM.

Patient should take a deep breath while the examiner presses deeply.

Any supraclavicular nodes that are enlarged will be felt as the patient inhales.

Palpation of thyroid gland

Evaluate consistency – normal consistent tissue, hardness possible tumour or scaring

Tender acute infections or haemorrhage into the gland

Palpated from front & back

In the anterior approach – face to face. Examiner by flexing the patient’s neck or turning the chin

slightly to the right, the SCM on that side is relaxed. The examiner’s right hand should displace the

larynx to the right & during swallowing the displaced right thyroid lobe can be palpated between the

examiner’s left thumb & index fingers. Procedure repeated for left side.

Posteriorly – stand behind patient. Place hands around the extended neck. Push trachea to right

with right. Patient swallows, while the examiners right hand rolls over the thyroid cartilage. On

swallowing the gland can be palpated as it lies against the SCM. The procedure repeated for left site.

Palpation of the Carotid Artery

Patient in a supine position. The index & third fingers are placed on the thyroid cartilage & then

slipper laterally between the trachea & the SCM. The CA pulse can be felt just medial to the SCM.

Palpation should be performed low in the neck to avoid pressure on the carotid sinus; pressure on

the carotid sinus would cause a reflex drop in blood pressure & heart rate. Indeed sinus massage is

sometimes used to reduce heart rate. Each CA artery should be evaluated separately.

Palpation of the jugular venous pulse

The pulsations of the IJV are beneath the SCM & are visible as they are transmitted through the

surrounding tissue. The vein itself not visible. Because the right IJV is straighter than the left, only

the right IJV is evaluated. Ng: although the EJV is easier to visualise, its pulsations are less accurate.

Clinical correlates

Proptosis: eyeballs bulging forwards – causes thyroid dysfunction or by mass in the orbit

A diffused enlargement thyroid gland will often cause generalised enlargement of the neck.

Superficial venous distension in the neck may be associated with a goitre.

The most common symptoms related to the neck include neck mass (lump or swelling) & neck

stiffness. If there is associated pain with a mass in the neck; an acute infection would be most likely.

Neck masses that have been present for only a few days = inflammation, months tumour. A mass

present for a long time without change in size would often be benign or congenital. Blockage of the

salivary gland duct may produce a mass that changes in sizes while the patient eats

The age of the patient is relevant in the assessment of a neck mass. A lump in the neck in a patient

under the age of 20 years may be an enlarged tonsillar lymph node or congenital mass. If the mass is

in the midline, it is likely to be a thyroglossal cyst. Between the ages of 20 & 40, thyroid disease is

more common.

The location is important: midline tend to be benign or dermoid cysts. Lateral masses freq.

neoplastic. Masses in the lateral upper neck may be metastatic lesions from tumours of the H&N,

whereas masses in the lateral lower neck may be metastatic from tumours of the breast, lung &

stomach. Hoarseness in association with a thyroid nodule suggests vocal cord paralysis by

compression of the recurrent laryngeal nerve by tumour.

Stiffness of the neck is usually caused by spasm of the cervical muscles & is commonly the cause of

tension headaches. A sudden occurrence of a stiff neck, fever & headache should be considered as a

sign of possible meningeal irritation. Neck pain may be associated with referred pain from the chest;

patients with angina or MI may complain of neck pain.

Session 9 –Cranial Nerves Olfactory (CI)

Optic (CII)

Oculomotor (CIII)

Trochlear Nerve (CIV)

Trigeminal (CV)

Abducent (CVI)

Facial (CVII)

Vestibulocochlear/auditory nerve (CVIII)

Glossopharyngeal (CIX)

Vagus (CX)

Accessory (CXI

Hypoglossal (CXII)

Oh (one nose) , Oh (2 eyes), Oh, To Touch And Feel Virgin Girls Vaginas & Hymens

Some, say, money, matters, but, my brother says big boobs matter more.

Nerves derived from the cervical plexus (is a plexus of the ventral rami of the first four cervical

spinal nerves which are located from C1 to C4 cervical segment in the neck) supply a portion of the

skin of the region. They innervate the back of the head, as well as some neck muscles. They are

numbered in order they arise from the brainstem & pass through foramina in the skull to supply the

structures.

Olfactory nerve – special sensory fibres supplies the nasal mucosa giving smell.

Bilateral loss of smell is usually of no significance, many common nasal infections impair the sense of

smell bilaterally. Some individuals are born with a bad sense of smell. Tumours or fractures often

involve damage to only one side. Sense of smell rarely tested unless there is traumatic damage to

CN1 or tumour in the anterior cranial fossa (ACF) or fracture of the cribriform plate

Optic Nerve – special sensory fibres supply the retina giving vision

Assessing visual field defects this is done by bringing a wiggling finger into view from the sides, from

above & below. The patients look straight ahead & say when a finder can be seen.

Damage from direct trauma to the orbit, pressure on optic pathway; laceration or intracerbral clot in

the temporal, parietal or occipital lobes of the brain

Oculomotor Nerve (C3)– motor fibres – extraocular muscles (except SO & lateral muscles) .

Autonomic fibres- PS acting on SM of sphincter papillae & ciliary body

Complete Oculomotor palsy affects most of the ocular muscles, the levator palpabrae superioris &

sphincter papillae. The superior eyelid droops (ptosis) & cannot be raised voluntarily because of the

unopposed orbicularis oculi supplied by facial nerve (CN 7). One or more ocular muscles may be

paralysed by head injury or brainstem disease resulting in double vision (diplopia).

Nerve palsy can occur from herniating uncus on nerve; fractures involving cavernous sinus;

aneurysms.

Trochlear Nerve- motor (C4– superior oblique muscle)

Damage from stretching of nerve during its course around brainstem; fracture of orbit inability to

look down when eye is adducted.

Abducent nerve – motor (C6 – lateral rectus muscle

Functional anatomy of CIII, CIV, CVI.

Extraocular muscles – patient is asked to look at finger as it is moved in directions that elicits

adduction & abduction of the eye, elevation & depression of the eye when it is adducted & elevation

& depression of the eye when it is abducted.

Levator palpabrae superoris – patient is asked to look upward so as to observe if elevation of the

eyelid accompanies this effort

PSNS pathway – constrictor papillae – shining a light into the eye; pupil should constrict – pupillary

light reflex is consensual – shining a light in one pupil only one eye causes both to constrict.

SNS pathway – dilator papillae – shielding an eye from the light; pupil dilates – reflex is consensual

Abducent nerve – most freq. damaged 1st nerve to be affected by septic thrombosis of the cavernous

sinus; aneurysm of the ICA within the cavernous sinus may put pressure on CN 6. Eye fails to move

laterally diplopia on lateral gaze.

Trigeminal nerve (CV) split into:

Vi – ophthalmic (sensory)

o skin of scalp & forehead, upper eyelid, dorsum of nose, cornea & conjunctiva

Responsiveness of the skin of the forehead to touch & prick

o Corneal reflex (blink reflex) – sensation via Vi to V > brain – fibres synapse with facial

neurones innervating the palpabrae portion of orbicularis oculi > contracts,

producing a blink (consensual)

o Corneal reflex disturbed if either the sensory or the motor limb is damaged; damage

of sensory limb > neither eyelid will blink – if cornea of one eye produces a blink in

the opposite eye, Vi is okay & the defect is in the facial nerve. As well as Vi it

depends on some parts of the facial nerve. To perform use a thin strand of cotton

wool & poke them in the eye with it. The patient requested to look right as the

cotton tip is brought in from the left side to touch the left cornea gently. A prompt

bilateral reflex closure of the eyes is the normal response.

Vii – maxillary (sensory)

o Sensory – skin of lower eyelid, cheek, upper lip; mucosa of nasal cavity & Paranasal

sinuses

o Palate & upper teeth

o Damage to this causes nasal, palatal & upper dental sensation to be reduced

(uncommonly tested)

Viii – mandibular (motor & sensory)

o Sensory – skin of temple cheek & chin, mucosa of inner cheek ant 2/3 of tongue &

lower teeth. Test – skin over chin (mental nerve) & side of cheek (buccal)

o Motor – muscles of mastication.

o Test both last two divisions by assessing the responsiveness of the skin over the

front of the cheek (infraorbital nerve) to touch & pain. general sensation to the front

of the tongue test for strength of the masseter & pterygoids.

Trigeminal nerve may be injured by trauma, aneurysms or meningeal infections. Injury to the nerve

may cause paralysis of the muscles of mastication (V3), loss of ability to appreciate tactile, thermal or

painful sensations in the face, cornea, conjunctiva & the loss of the corneal reflex.

Testing the sensory components of the nerve - patient to close eyes & respond to when they are

touched. A piece of gauze is applied to one side of the forehead & then to the corresponding

position on the other side. Then cheeks then jaw.

Testing motor components – patient bite down or clench his teeth while the masseter & temporalis

muscle are palpated bilaterally. Unilateral weakness will cause the jaw to deviate towards the side of

the lesion.

Facial nerve (CN VII)

Motor – muscles of facial expression

Special sensory – ant 2/3 of tongue,

Autonomic – PSNS – secretomotor to Submandibular, sublingual glands, glands of nasal mucosa,

Paranasal sinuses, palate, & the lacrimal gland

Course of nerve: internal acoustic meatus in petrous temporal bone through facial canal exits

stylomastoid foramen through parotid gland

Branches inside facial canal:

Greater petrosal nerve – PS to lacrimal; sensory taste to palate

Nerve to stapedius – innervates stapedius muscle

Chorda tympani – PS to submandibular & sublingual; special sensory taste to anterior 2/3 of

tongue

Outside skull branches (distal to stylomastoid foramen):

Posterior auricular nerve – controls movements of some of the scalp muscles around the ear

Branch to posterior belly of Digastric & Stylohyoid muscles

5 facial branches:

o Temporal

o Zygomatic

o Buccal

o Mandibular

o Cervical

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Damage of the facial nerve (outside the facial canal) results in paralysis of MOFE. Damage within

posterior wall of the tympanic cavity (chorda tympani) taste to ant 2/3rd of tongue & salivation &

lacrimation disturbed.

Surgery on the middle ear may damage the facial nerve within the labyrinthine wall of the tympanic

cavity. Tumours within the petrous part of the temporal bone will affect the facial nerve

Facial nerve tests- raise eyebrows, wrinkle forehead (frontalis), close the eyes tightly (orbicularis

oculi), broad smile for several muscles for symmetry, puffing out of the cheeks (buccinators) tests

orbicularis oris as well.

The most common non-traumatic cause of facial paralysis is inflammation of the facial nevre near its

exit from the cranium at the stylomastoid foramen. The inflammation causes oedema &

compression of the nerve (Bell’s palsy).

As the branches of the facial nerve are superficial, they are subject to injury in wounds, cuts & in

child birth. The nerve & its branches pass through the parotid gland, they are vulnerable to injury

during surgery on the gland or disease. Parotid gland disease often causes pain in the auricle of the

ear, EAM, temporal region & the TMJ

Assessment of facial nerve function - patients asked to bare the teeth; puff out his cheeks

(buccinators) against resistance & wrinkle the forehead. Examiner should note any asymmetry.

Then patients is asked to close his eyes tightly (orbicularis oculi) while examiner tries to open them;

the palpebral part of orbicularis oculi gently closes the eyelids. Each eye examined separately, & the

strengths are compared.

Vestibulocochlear nerve (CN VIII) – special sensory supply to the organs of balance & hearing

Assessment of sense of equilibrium or freq. of auditory sensitivity is a specialist area

Lesion – tumour of nerve (acoustic neuroma) progressive hearing loss; tinnitus

Glossopharyngeal nerve (CN IX)

Motor

Branchiomotor –Stylopharyngeus; swallowing

Visceromotor (PSNS) – parotid gland (test salivation)

Sensory

Viscerosensory – carotid body & sinus (monitor BP & oxygen levels), pharynx & middle ear

special sensory – posterior 1/3 of tongue (for taste can test)

General sensory – cutaneous sensation from external ear

Test for CN IX function is the gag reflex; constricts of a pharyngeal constriction when the back wall of

the oropharnyx is touched; CIX is the sensory limb of the reflex & the vagus is the motor limb.

Damage – brainstem lesion or deep laceration of neck los of taste on posterior 1/3; loss of

sensation on affected side of soft palate

Vagus Nerve (CN X)

Motor –

Intrinsic muscles of the larynx & pharynx muscles of the palate

Smooth muscle- bronchi, digestive tract

Secretomotor – thoracic & abdominal muscles

Sensory

external ear, auditory canal & eardrum

Pharynx & larynx

Visceral sensation – thorax & abdomen.

Special sensory – taste from epiglottis & palate

Damage of right recurrent laryngeal nerve results in the vocal cord on that side is slightly adducted;

symptoms are hoarse voice, weak cough, risk of aspiration of fluids

Left recurrent laryngeal nerve (lower than right) may be affected in a bronchial or oesophageal

carcinoma or enlarged mediastinal lymph nodes or become stretches over an aneurysm of the aortic

arch.

Enlarged left atrium (mitral stenosis) may produce LRN palsy by pushing up the left pulmonary artery

which compresses the nerve against the aortic arch.

Damage to the superior laryngeal nerve in surgery to the neck > external branch lies closes to

superior thyroid artery; may be injured in ligating this vessel; may cause weakness of phonation due

to loss of tone of the cricothyroid muscle.

Accessory Nerve (CN XI)

Motor – stenocleidomastoid & trapezius muscle

Damage can occur from laceration of the neck, dissection of deep cervical lymph nodes

Testing integrity of the SCM & TM:

SCM – turn head to one side against resistance

Trapezius – shrug shoulders against resistance; only tests upper fibres – these are the ones

that receive most innervation from the CN XI

Hypoglossal nerve (CN XII)

Motor –muscles of the tongue

Damage – neck laceration or basal skull fractures

Protruded tongue deviates towards affected side; moderate dysarthria (disturbance of articulation)

To test- sticking out of the tongue & wiggling it from side to side; if it can be wiggled to one side, the

muscles of that side are paralysed.