Head/Neck Clinical Correlations

Injury to laryngeal nerves

Inf. laryn. n. vulnerable during thyroidectomy

Damage to inf laryngeal n.

- Paralysis of vocal fold

- (unilateral) weak voice

- Near-complete loss of voice and stridor (bilateral)

Damage to superior laryn. n.

- Monotonous voice

- Damage to external branch to cricothyroid m.

Fxs of laryngeal skeleton

Blows/compressions to larynx

Can cause

- Submucosal hemorrhage

- Edema

- Resp. obstruction

- Hoarseness

- Loss of phonation

Thyroid, cricoid, arytenoid cartilages ossify with age (start ~25yo)

Foreign body aspirations

Foreign object passes into vestibule of larynx, trapped superior to vocal folds

Pt freaks out, mm. spasm, closing vocal folds/rima glottidis

Adenoiditis

Inflammation of the pharyngeal tonsils (adenoids)

Can obstruct airflow from nasal cavity to nasopharynx

- causes mout breathing

Infection can spread to tubal tonsils

- can cause closure of the pharyngotympanic tube from swelling

- impairs hearing

Can also spread to middle ear (otitis media)

Foreign body in laryngopharynx

Can lodge in piriform recess

- if sharp can pierce mucous membrane, damage nn.

Tonsillectomy

Removal of palatine tonsil

The tonsil itself and fascial sheet are both removed

Often bleed heavily due to rich blood supply

Complications can include nicking the glossopharyngela n. (CN IX) and/or internal carotid a., lies directly lateral to tonsil.

Zones of penetrating trauma

Zone 1

- clavicle/manubrium to inf. border of cricoid cartilage

Zone 2

- Cricoid cartilage to angle of mandible

Zone 3

- Angles of mandible and up

Zones 1/3 can cause airway onstructions and are greatest risk of morbidity and mortality (harder to visualize damage)

Zone 2 more commonly injured and easier to fix (vessels easily compressed)

Infection spread in neck

Deep cervical fascia layers help to prevent spread of pus

Infections between investing and visceral fascia can spread to thorax

Infections posterior to prevertebral can enter the retropharyngeal space

- can cause difficulty swallowing/speaking

- high mortality rate (invasion of mediastinum)

Congenital toticollis

Contraction of cervical mm. causing twisted neck/slanted head

Commonly caused by fibrous tumor in SCM

Muscular torticollis: tearing of SCM from pulling head during delivery

- hematoma -> fibrous mass -> traps CN XI (spinal acc. n.)

Nerve blocks

Anesthetics injected along posterior SCM border

Typically done at cervical plexus to numb entire area

Subclavian venipuncture

Central line placement

Provide fluids, nutrition, measure venous pressure

More direct route to heart

Used for patients requiring more frequent IV drugs

Accessory thyroid tissue

Pyramidal lobe

-Remnant of thyroglossal duct

- Thyroid descending in the endodermal tube during dev.

- Endodermal tube failed to atrophy

Strokes

ischemic stroke- caused by blood clot

- embolism, thrombosis, cerebral/subarachnoid hemorrhage

hemorrhagic stroke- caused by ruptured blood vessels (brain bleed)

-rupture of a. or aneurysm

- saccular aneurysm is a common type and a "berry" aneurysm

- higher risk in HTN

TIA (Transient ischemic attack)

Temporarily diminished blood supply to the brain

- Not completely blocked (stroke)

A few minutes to an hour

Higher risk of MI or ischemic stroke

- clot could get caught in a smaller a.

Neruologic symptoms

- staggering

- Dizziness, lightheaded, faintness

- Paresthesia

Infection of parotid gland

Via pathogens in blood

Severe pain, glands swell, capsule doesn't

(worse when chewing)

Can cause pain in other structures innervated by auricotemporal n. (TMJ, temporal region, auricle, external acoustic meatus)

Parotidectomy

80% of salivary tumors are in parotid gland

Must identify and preserve facial n. (CN VII)

- Use CT/MRI to avoid nn.

TMJ dislocation

Excessive contraction of lateral pterygoids can pull the head of the mandible out of the mandibular fossa

-anterior to the articular tubercle

Nasal Fxs

Common in auto/sports accidents

Deformation of the nose can break the bones/cartilage

Typically causes a nosebleed (very vascular)

Cribiform plate at risk

- CSF rhinorrhea

- Anosmia

Septal deviation

Can be a birth injury or caused by trauma to the nose

Can be corrected surgically

Can interfere with breathing or increase snoring if severe

Rhinitis

Infections can spread through the head

Anterior cranial fossa via cribiform plate

Nasopharynx and retropharyngeal soft tissues

Middle ears through pharyngotympanic tube

Paranasal sinuses (sinus infection)

Lacrimal apparatus and conjuctiva (conjunctivitis)

Epistaxis (Nosebleed)

usually arise from Kiesselbach area

Also associated with infections and HTN

Spurting blood from nose (arterial)

Mild (venous)

Sinusitis

Infection and swelling of the mucosa in the sinuses

Can block an opening if severe

Infection of ethmoid cells

If ethmoid air cells can't drain, infections may break through medial wall of orbit

Can cause blindness

-Some posterior cells are very close to optic canal and could infect the optic n. or ophthalmic a.

Can cause inflammation of the dural sheath of optic n (optic neuritis)

Infection of maxillary sinus

Most commonly infected sinus

Teeth and maxillary sinus

Maxillary molars closely associated with maxillary sinus

Fractures of tooth roots during removal can be driven into the sinus, causing infection

Also why sinus problems can cuase toothaches

Otitis externa

Swimmers ear

External ear infection

- Bacteria or fungal

- Excess moisture in ear

Causes inflammation of auditory canal

- Reduced hearing

Treat with abx

Patulous eustachian tube

Pharyngotympanic tube remains open due to weak musculature or valve weakness

Causing pt to hear annoying rushing air sound during breathing or blood pumping or echo of their own voice

Increased likelihood of middle ear infections

Head injuries and intracranial hemmorhage

Extradural (epidural) hemorrhages are usually arterial, caused by tearing of the middle meningeal artery after a hard blow to the head. Blood collects between the dura and the skull, leading to an epidural hematoma. Patients often have a brief loss of consciousness, a temporary lucid period, then declining mental status as pressure on the brain increases, requiring urgent evacuation.

A "subdural hematoma" more accurately refers to a dural border hematoma, where venous bleeding splits the cell layer between the dura and arachnoid. This typically results from tearing of bridging veins after the brain shifts within the skull. Symptoms may appear slowly over weeks.

Subarachnoid hemorrhage involves arterial bleeding into the subarachnoid space, usually from a ruptured aneurysm, or sometimes trauma. It causes irritation of the meninges, leading to sudden severe headache, stiff neck, and possible loss of consciousness.

Facial injuries

Because the face does not have a distinct layer of

deep fascia and the subcutaneous tissue is loose

between the attachments of facial muscles, facial

lacerations tend to gape (part widely). Consequently, the

skin must be sutured carefully to prevent scarring. The

looseness of the subcutaneous tissue also enables fluid

and blood to accumulate in the loose connective tissue

after bruising of the face. Facial inflammation causes considerable swelling.

Bells palsy

Injury to the facial nerve (CN VII) causes paralysis of facial muscles on one side, known as Bell palsy. The face sags, and expressions become distorted. Weakness of the orbicularis oculi makes the lower eyelid droop, preventing tears from spreading and putting the cornea at risk for drying and ulceration. If the buccinator or orbicularis oris are affected, food collects in the cheek, speech becomes difficult, and the mouth may droop, causing drooling. People with this condition often wipe away tears and saliva that escape from the weakened eyelid and mouth.

Fx of the orbit

Medial and inferior orbital walls are very thin

Can lead to blowout fractures

Medial blowout can impact ethmoid and sphenoid sinuses

Inferior blowout can involve maxillary sinus and potentially trap inferior rectus m.

Intraorbital bleeding can cause eye to protrude due to increased pressure

Orbital tumors

Malignant tumors of sphenoid or ethmoid sinuses may erode bone into the orbit

Tumors may also spread into orbit via superior orbital fissure

Can compress optic n., affecting vision

Inflammation of palpebral glands

Any eyelid gland can become inflamed (infection, dust)

If ciliary gland, develop sty (hordeolum)

If sebaceous gland, develop chalazion

Dacryocystitis

Dacryo- Tear

Cysta- Sac

Infection of the lacrimal sac caused by a blocked nasolacrimal duct

Usually Staphylococcus aureus

Dacryoadenitis

Dacryo: Tear

Adeno: gland

Infection of the lacrimal gland

Upper eyelid shows characteristic s-curve and tender

Staphylococcus, mumps, Epstein-Barr virus (mono)

Retina exams

Hypertension: larger distended vessels

Diabetes: Hemorrhages, hard exudates

Glaucoma

Aqueous humoral drainage must be sufficient pressure increases

This cascades to apply pressure in posterior chamber, and then vitreous chamber

This puts pressure on the retinal nerve fibers which converge at the optic nerve

Retinal detachment

Separation between the neural and pigmented layers of the eye

Can be caused by trauma, may be delayed

Signs include increased floaters in vision, flashes of light

Presbyopia and Cataracts

Presbyopia: lens becomes harder and flatter with age, reduces focusing power

Cataracts: loss of transparency in the lens (cloudiness)

Can either extract lens and replace with an artificial lens, or can remove entire capsule and place artificial lens in the anterior chamber

Pupillary light reflex

The pupillary light reflex is checked with a penlight and involves CN II (sensory) and CN III (motor). Light entering one eye causes both pupils to constrict because each retina sends signals to both sides of the brain. The sphincter pupillae is controlled by parasympathetic fibers, so damage to these fibers results in a dilated pupil. A slow pupillary response on the same side is often the first sign of oculomotor nerve compression.

Oculomotor nerve palsy

Complete oculomotor nerve palsy paralyzes most eye muscles, the levator palpebrae superioris, and the sphincter pupillae. The upper eyelid droops and cannot be lifted, the pupil becomes fully dilated and unreactive, and the eye rests "down and out" because the lateral rectus and superior oblique act unopposed.

Abducent nerve palsy

When the abducent nerve (CN VI) supplying only the lateral rectus is paralyzed, the individual cannot abduct the pupil on the affected side. The pupil is fully adducted by the unopposed pull of the medial rectus.

Sublingual absorption of drugs

For quick transmucosal absorption of a drug—for instance, when nitroglycerin is used as a vasodilator in angina pectoris (chest pain)—the pill (or spray) is put under the tongue, where the thin mucosa allows the absorbed drug to enter the deep lingual veins in less than a minute.

Dural origin of headaches

The dura is very sensitive to pain, especially near venous sinuses and meningeal arteries. Many headaches are thought to come from dural irritation, including headaches after a lumbar puncture. When CSF is removed, the brain can sag slightly and pull on the dura, triggering pain. Lying flat after the procedure helps reduce this pull and lowers the chance of headache.

Cerebreal injuries

Cerebral contusions are brain bruises caused by trauma that strips or tears the pia, allowing blood into the subarachnoid space. They result from sudden impact between the brain and skull and can cause prolonged loss of consciousness. Cerebral lacerations, often from depressed fractures or gunshot wounds, rupture blood vessels and increase intracranial pressure, leading to brain compression. Compression can also result from blood collections, blocked CSF flow, tumors or abscesses, and brain swelling from edema.

Hydrocephalus

Overproduction of CSF, obstruction of its flow, or interference with its absorption results in an excess of CSF in the ventricles. When it occurs in infants and young children, the head enlarges, a condition known as hydrocephalus. Excess CSF dilates the ventricles, thinning the surrounding brain, and, in infants, separates the bones of the calvaria because the sutures and fontanelles are still open.

Leakage of CSF

Fractures of the middle cranial fossa can cause CSF to leak from the ear (CSF otorrhea) if the meninges and eardrum are torn. Fractures of the anterior cranial fossa, often involving the cribriform plate, can cause CSF to leak from the nose (CSF rhinorrhea). Both are key signs of cranial base fractures and raise the risk of meningitis from infection spreading through the ear or nose.

Anosmia - Loss of smell

Loss or decreased sense of smell

Can occur with: aging, smoking, cocaine, viral/allergic rhinitis, trauma

Associated with loss/alteration of taste as main symptom

May be associated with basilar skull fracture, can shear the olfactory nn. as the bone fragments move

Visual field defects

Damage to CNII

- blindness in the ipsilateral eye

Damage to optic chiasm

- Loss of lateral(temporal) vision bilaterally -tunnel vision

- only binocular zone functional

Damage to lateral portion of optic chiasm

- loss of medial(nasal) vision in ipsilateral eye

Damage to optic tract

- Loss of vision in the same side of the visual field of each eye

Damage to the optic radiations in the brain

- Same as above

Damage to optic radiations in the brain, but occipital pole spared

- same as effect 4, but the macular region is spared

- Macular region inputs on occipital pole

Demyelination diseases and optic nerve

Optic nn. are tracts of the CNS

Glial cells (oligodendrocytes) form myelin sheath rather than neurolemma (Schwann cells, PNS)

Demyelination of optic nn. = optic neuritis

Susceptible to demyelination diseases such as multiple sclerosis

Lyme disease, toxoplasmosis, HIV, and systemic viral diseases, can also cause optic neuritis

Non-infectious cuases more common

Causes vision loss

- insulation of nerve is gone, limits conduction of impulses

Ocular palsies CNIII

Complete palsy

- ptosis(drooping) of superior eyelid

- eyeball abduction (durected down and out)

- No pupillary (light) reflex

- Dilation of pupil

- No lens accommodation

Partial palsy

Usually due to rapidly increased ICP (hematomas)

- often compress CNIII against petrous portion of temporal bone

Parasympathetic fibers are superficial, affected first

Ocular palsies CNIV

Trochlear nerve

Rarely injured in isolation

Diplopia (double vision) when looking down

- paralysis of superior oblique

- cant assist inferior rectus in depression of eye

Ocular palsies CNVI

Abducens nerve

Long intracranial course, so can be stretched with increased ICP

Space-occupying lesion

- can cause partial paralysis of lateral rectus

Complete lesion causes medial deviation of the affected eye

- Paralysis of lateral rectus

- cannot fully abduct

- fully adducted at rest due to unopposed medial rectus

Inury to trigeminal nerve

Trauma, tumors, aneurysms, meningeal infections

Symptoms:

- paralysis of mastication mm.

- loss of general sensation to face

- loss of corneal and sneezing reflexes

Trigeminal neuralgia

- affects sensory root

- Extreme episodes of pain

- Usually restricted to mandibular and/or maxillary divisions

Virus hideout

Viruses tend to follow nerve paths

EX: Herpes simplex 1, Varicella zoster

The viruses retreat into the cranial foramina and after facial infections and lie dormant

Harbored around trigeminal ganglion

Anytime in the future when immunosuppressed, viruses can follow the nerve back out and reinfect

Injury to facial nerve

Proximal lesion

Near origin or geniculate ganglion

Loss of motor, taste, and autonomics

Motor paralysis of facial muscles (bells palsy)

Central lesion (CNS)

paralysis of mm. of inferior face on ipsilateral side

Forehead not affected because of bilateral innervations

Corneal reflex

Blinking when the cornea is lightly touched

Loss of this reflex can occur with lesion to EITHER the ophthalmic n. or facial n.

Ophthalmic n. manages the afferent portion of this reflex

Facial n. manages the efferent portion of this reflex

injury to vestibulocochlear nerve

Vestibular and cochlear nn. are functionally independent

Peripheral lesions can affect both due to proximity

Symptoms

-tinnitus (ringing or buzzing in ears)

-vertigo (dizziness, loss of balance)

-impaired/loss of hearing

Conductive hearing loss

Related to external or middle ear

Causes problems with sound being transmitted to the inner ear

Causes can include otitis media, osteosclerosis

Sensorineural Hearing loss

Related to inner ear (CN VIII, hair cells) or the brain

There's a problem with the brain's ability to percieve sound (cochlea, or the path between cochlea and brain)

Could be nerve damage or a lesion pressing on that nerve

Acoustic neuroma

Benign tumor of the neurolemma

Begins in vestibular n.

Initial presentation is CN VIII dysfunction

- unilateral hearing loss

- balance issues

As tumor grows, can involve CNV or VII

- could cause trigeminal sensory loss or facial palsy

Continued growth could compress CNIX, cerebellum, and brainstem

Lesions of glassopharyngeal nerve

Usolated lesion

Unilateral loss of taste in the posterior 1/3 of the tongue and gag reflex

Changes in swallowing (pharyngeal m. paralysis)

Palatal deviation to the unaffected side (pharyngeal m. paralysis)

Rarely occurs in isolation

usually involve nearby nerves

- CN IX, X, XI affected, jugular foramen syndrome

Lesions of vagus nerve

Isolated lesions are uncommon

Lesions of pharyngeal branches

- Dysphagia (difficulty swallowing)

- Uvula deviation to unaffected side

Lesions of superior laryngeal n.

- Anesthesia of superior larynx

- Paralysis of cricothyroid m.

Lesions of recurrent laryngeal nn.

- Hoarseness and dysphonia

- Bilateral = aphonia and inspiratory stridor

Proximal lesions affect pharynx, larynx, and viscera

Injury to spinal accessory nerve

Susceptible to damage during surgery

Lesions cause atrophy of SCM and trapezius

- Weakness in shoulder elevation (trapezius)

- Impairment of neck rotation (SCM)

Injury to hypoglossal nerve

Paralysis to ipsilateral side of the tongue

- causes dysarthia (slurred/slow speech)

May eventually atrophy the affected lingual mm.

When protruded, deviates towards the paralyzed side

- unimpeded action of the mm. on the unaffected side, push tongue to the affected side

Deafness

Conductive Hearing Loss: Causes problems with sound being transmitted (conducted) to the inner ear

Sensorineural Hearing Loss: There’s a problem with the brain ability to perceive sound (cochlea, or the path between cochlea and brain)