The Ears Randa M. Albusoul
Anatomy Structure of the Ear: The ear is organ of hearing. It comprises of three parts: Outer ear Middle ear Inner ear
Structure of the outer Ear: • It is composed of two parts; auricle and ear canal. • Auricle is cartilage cover by skin and has firm elastic consistency. • The auricle function is to gather sound waves.
• The ear canal is approximately 2.5 cm long. • The outer portion of the canal consists of cartilage and skin, that is hairy and contains glands that produce earwax (cerumen). • The inner portion consists of sensitive, thin, hairless skin, that is surrounded by bone. • The canal has slight S-curve in adults. • The canal ends with ear drum (tympanic membrane).
• Mastoid process (the lowest portion of mastoid part of the temporal bone) can be palpable behind the lobule. L ANDMARK • The earwax is yellow, waxy material that lubricates and protects the ear; forms a sticky barrier that helps keep foreign bodies from entering and reaching tympanic membrane. • Earwax migrates out of the ear canal due to chewing and talking movements.
Tympanic membrane: • Separates the external and middle ear. • Tilted obliquely to the ear canal, facing downward and somewhat forward. • Translucent membrane with a pearly gray color and a prominent cone of light (reflection of the otoscope light). • Cone shaped light prominent at 5 o ’ clock position in Rt ear and 7 o ’ clock position in Lt ear.
• Oval and slightly concave. • Pulled in at its center by one of the middle ear ossicles-malleus. • The parts of the malleus that can be visible through the drum are: Umbo, manubrium, and the short process. • Pars Flaccida- small, slack superior section of the tympanic membrane. • Pars Tensa-The remainder of drum that is thicker and more taut. • Annulus is outer fibrous rim of the drum.
Structure of the middle Ear: • Is an air-filled cavity inside the temporal bone that transmits sound by three tiny bones (ossicles) namely malleus, incus, stapes. • It is connected with a nasopharynx by eustachian tube. • The eustachian tube is normally closed but it opens with swallowing or yawning. • It is approximately 3.5 cm long and its function is pressure equalization (middle ear and atmosphere) and mucus drainage from the inner ear.
Function of the of middle Ear: 1. Conducts sound vibrations from outer ear to central hearing apparatus in the inner ear. 2. Protects inner ear by reducing the amplitude of loud sounds. 3. Its Eustachian tube allows equalization of air pressure on each side of tympanic membrane so membrane does not rupture with change in pressure.
Structure of the inner Ear: • Holds the sensory organs for equilibrium and hearing. • Consists of the vestibule and the semicircular canals and the cochlea (snail shell) that contains the central hearing apparatus. • The inner ear is not accessible to examination, however, its function can be assessed.
• The inner ear contains bony labyrinth and membranous labyrinth.
• There are two openings into the inner ear; round window and oval window. • round window is closed off from the middle ear by the round window membrane, which vibrates with opposite phase to vibrations entering the inner ear through the oval window. It allows fluid in the cochlea to move, which in turn ensures that hair cells of the basilar membrane will be stimulated and that audition will occur.
Pathways of hearing: Conductive phase (external ear to the middle ear): vibrations of sound pass through the air of the external ear then through the eardrum and ossicles to the cochlea. Sensorineural phase (cochlea and cochlear nerve): the cochlea senses and codes the vibrations, and nerve impulses are send to the brain through cochlear nerve.
• The normal pathway of hearing is air conduction (AC): It is the most efficient • Alternate route of hearing is bone conduction (BC): Vibrations are transmitted directly to the inner ear and to cranial nerve VIII. Equilibrium: the labyrinth within the inner ear senses the position and movements of the head and helps to maintain balance.
Subjective Data Concerning symptoms of the ear are: Hearing loss Earache (otalgia) Discharge (otorrhea) Tinnitus Vertigo The opening questions may be: How is your hearing? Have you had any troubles with your ears?
If the patient has any problem / symptom do further assessment to that symptom using OLD CART questions . (return to the book for examples of the questions for each symptom) Hearing loss • Distinguish between two basic types of hearing impairment. (book page 253 +281). • Ask patient if she/he is taking ototoxic medication.
Ototoxic (ear-damaging) medications are medications that damage ears (inner ear: cochlea) causing hearing loss especially in older adults. Examples: Aspirin NSAIDs Antibiotics especially Aminoglycosides (gentamycin, streptomycin, neomycin) Loop diuretics (furosemide: lasix) Chemotherapy: cyclophosphamide, cisplatin, bleomycin. The first symptoms of toxicity are tinnitus and vertigo .
Clues to possible hearing loss: • Person lip reading or watching face & lips closely rather than your eyes. • Frowning or straining forward to hear. • Posturing of head to catch sounds. • Misunderstands questions or frequently asks you to repeat. • Acts irritable when your voice is raised. • Person ’ s speech sounds garbled. • Inappropriately loud voice.
Earache Otitis media: medical term for middle ear infection Otitis externa: inflammation of the outer ear and ear canal .
Otitis externa
Tinnitus: Is a perceived sound that has no external stimulus and commonly is heard as musical ringing or roaring noise. Vertigo: refers to perception that the patient or the environment is rotating or spinning. If labyrinth of inner ear becomes inflamed, or there are lesions on the vestibulocochlear nerve it feeds wrong info. to the brain. This creates staggering gait, and a strong, spinning, whirling sensation called vertigo.
What is a difference between vertigo, presyncope, and dysequilibrium? Page 277.
Past history: Congenital hearing loss Removal of cerumen Ear surgery Trauma Infection Exposed to hazardous noise levels History of syphilis, rubella, meningitis.
Family history: Hearing loss Otitis media Allergies Smoking Lifestyle habits: Are you exposed to loud noise?
Objective Data Inspect and palpate the external ear: • Size and shape and ear alignment: ears are equal size bilaterally with no swelling or thickening, taking in consideration a normal familial trait. • Skin Condition: skin color is consistent with facial skin color, skin intact, with no lump or lesions. • Tenderness: move the auricle and push the tragus, should feel firm with no pain. otitis externa? • External auditory meatus: cerumen appearance- color varies from yellow to brown or black; may be moist and waxy to dry. Any other discharge? Inflammation?
Inspect ear using otoscope: • Tilt person ’ s head slightly away from you toward the opposite shoulder. • Choose the largest ear speculum that the canal will accommodate. • To straighten the ear canal, pull the auricle up and back on an adult or older child; Pull the auricle down on an infant and a child under 3 yrs. • Once in place, you may need to rotate the otoscope slightly for better visualization.
Inspect the eardrum: Color:shiny and translucent with a pearl-gray color. Cone-shaped light reflex. Perforated eardrum Section of malleus. Integrity: intact eardrum.
Auditory Acuity: • Whisper-Voice test. Test one ear at a time, ask pt to close her other ear, stand behind the pt, whisper softly toward unoccluded ear, increase intensity of sound if necessary. #testing of ear and bone conduction is done if the patient has problems in hearing … • Weber test: after making tuning fork Vibrating, ask about where the pt hear it. normally heard in the midline. In unilateral conductive hearing loss sound is heard in impared ear.
In unilateral sensorineural hearing loss it is heard in the good ear. • Rinne ’ test: compare air conduction (AC) with bone conduction (BC). Place vibrating tuning fork on the mastoid bone, when the pt can no longer hear the sound, quickly place the fork close to the ear, and ask if the sound can be heard again. • Conductive hearing loss: BC=AC, or BC>AC. • Sensorineural hearing loss: AC>BC.
Romberg test: Test-assesses the ability of the vestibular apparatus in the inner ear to help maintain standing balance. Ask patient to stand up with feet together. When stable have pt close eyes wait about 20 seconds; slight swaying may occur. Positive Romberg ’ s – loss of balance that occurs when closing eyes.
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