- outer 1/3 covered with skin, produces cerumen

- inner 2/3 hairless and glandless, sensitive to pain

- curved, pointing inward, forward, and upward in adults

Auditory Canal

- teeth, tonsils, pharynx, cervical lymph nodes, larynx

Locations that refer pain to ear

- infection of the external auditory canal

- usually caused by bacteria after swimming or with trauma

- signs/symptoms include pain, erythema, swelling of ear canal, tenderness with pressure over tragus

External otitis

- life threatening form of external otitis

- occurs in diabetics

- Pseudomonas aeruginosa is the offending organism

- osteomyelitis of temporal bone is a common complication

Malignant external otitis

- umbo or end of malleus

- handle of malleus

- short process of malleus

- incus

Visible bony landmarks of tympanic membrane

- more prevalent part of the tympanic membrane on inspection

Pars tensa

- inflammation, opacification, calcium deposition, perforations and evidence of middle ear fluid

Tympanic membrane findings

- this radiates peripherally from the umbo and is directed anteriorly and inferiorly

Cone of light

- progressive bony stenosis of the external ear that is associated with chronic exposure to cold water (surfer/scuba diver)

- may interfere with normal clearance of cerumen --> conductive hearing loss

- increases the likelihood of infection

Exostosis

Exostosis

- progressive bony stenosis of the external ear that is associated with chronic exposure to cold water (surfer/scuba diver)

- increases the efficiency of hearing by amplifying sound 20 times

- part of middle ear proper

Tympanic membrane

- stimulated by rotational motion

- found in the petrous portion of the temporal bone

Semicircular canals

- stimulated by linear acceleration and gravitational force

Utricle and saccule

- cold water irrigation of the TM causes nystagmus in this direction

Toward the opposite side, away from stimulus

- warm water irrigation normally causes nystagmus in this direction

Toward the same side, toward from stimulus

- interruption in transmission of sound from the auditory canal to the oval window

- commonly caused by middle ear effusion in children, otosclerosis in adults

- other causes: perforated eardrum, cerumen impaction, foreign body in ear canal, otitis externa or media

Conductive hearing loss

- degenerative condition that causes fixation of the stapes to the oval window as a result of bone formation within the labyrinth

- most common cause of conductive hearing loss in adults

Otosclerosis

- indicates a problem in the inner ear, CN VIII, or CNS

- causes includes exposure to loud noise, Meniere's disease, 8th nerve injury from infections or medications, aging (presbycusis)

Sensorineural hearing loss

- pt asked to localize sound following a 512 Hz tuning fork placed in the midline of the pt's forehead

- sound should localize to midline

- sound localizes TOWARDS conductive hearing loss and AWAY from sensorineural hearing loss

Weber test

- pt compares intensity of sound when tuning fork is placed over the mastoid and when the prongs are held close to ear

- tuning fork should be louder next to ear

- conductive hearing loss is indicated by the sound being louder at the mastoid

Rinne test

- acute infection of the lining of the middle ear

- eustachian closure creates vacuum that causes N2 and O2 to be reabsorbed from air space by mucous membranes --> retraction of TM or transudation of fluid

- fluid serves as culture medium for bacteria

- Streptococcus pneumoniae and/or Hemophilus influenza

Purulent otitis media

- otitis media is one of the most common reasons that this population sees a doctor

Small children

- Mild-to-moderate pain, conductive hearing loss, fever, red and bulging TM

- pressure on tragus or pinna does not intensify pain

Symptoms of purulent otitis media

- a sudden resolution of otitis media pain and pressure could indicate this

TM rupture

- fluid accumulation in the middle ear without infection

- contributing factors that increase the likelihood of this are allergic inflammation and overgrown adenoidal tissue

- pain is lacking with straw colored fluid behind TM

- in adults, 1 episode prompts an evaluation for nasopharyngeal carcinoma

Serous otitis media

Serous Otitis Media

- fluid accumulation in the middle ear without infection

- pain is lacking with straw colored fluid behind TM

- skin growth that occurs in the middle ear due to repeated infection and chronic negative pressure

- often a cyst of pouch that sheds layers of old skin that build up in the ear

- can release enzymes that destroy the TM, ossicles, CN V

Cholesteatoma

- can have foul odor, pressure, hearing loss, aching (at night), dizziness, facial weakness, deafness, brain abscess, meningitis

Symptoms of choleastoma

- 75% of people older than 80 years have some degree of this

Presbycusis

- second most common disorder of the inner ear

- defined as a sensation of movement, typically rotary or spinning

- most common cause is peripher vestibulopathy from viral infections (labrynthitis), benign positional vertigo, or Meniere's disease

- severe for a few days then resolves completely in wks

Vertigo

- Dix Hallpike maneuver, Epley maneuver

- assess for canalithiasis of posterior semicircular canal

Tests for vertigo

- 3rd most common inner ear disorder

- perceived sensation of sound in the abscence of an acoustic stimulus

- may be pulsing, clicking, ringing, or roaring

- may be subjective or objective

Tinnitus

- present if examiner can also hear sound

- causes include tonic muscle contraction of pharyngeal or inner ear muscles and arterial bruits, AV fistulas or venous hums

Objective tinnitus

- present when the sound is inaudible to the examiner

- may be precipitated by a loud noise, cerumen impaction, otosclerosis, otitis media, eustachian tube dysfunction, diabetes mellitus or HTN, MS, aspirin, aminoglycoside antibiotics

Subjective tinnitus

- hearing loss, vertigo, and tinnitus

- caused by over-production or under-absorption of endolymphatic fluid within the membranous labyrinth

- leads to cochlear tearing and hair cell death

- found in 30's and 40's

Meniere's disease

- Benign paroxysmal positional vertigo

- vertebral-basilar insufficiency, migraine

- Meniere's disease

- Viral labyrinthitis

List of common causes of vertigo

(ascending duration)