Audiology Chapter 9 – The Middle Ear Vocabulary

40 vocabulary flashcards covering middle-ear anatomy, physiology, audiologic concepts, and common pathologies described in Chapter 9.

Middle Ear (Tympanic Cavity)

Air-filled space between the tympanic membrane and inner ear that houses the ossicles, muscles, ligaments, and opening to the eustachian tube.

Ossicular Chain

Series of three tiny bones (malleus, incus, stapes) that transmit and amplify vibrations from the eardrum to the oval window.

Malleus

‘Hammer’-shaped first ossicle; its manubrium is embedded in the tympanic membrane and its head connects to the incus.

Incus

‘Anvil’-shaped middle ossicle; body articulates with the malleus and its lenticular process joins the stapes.

Stapes

Smallest bone in the body; ‘stirrup’-shaped; head meets the incus and footplate fits into the oval window.

Eustachian Tube

Canal connecting middle ear to nasopharynx; equalizes air pressure and drains fluid; angled 30° and ~35–38 mm in adults.

Impedance Matching

Middle-ear process that adds ~30 dB of gain via ossicular lever action and TM-to-oval-window area ratio, offsetting air-to-fluid energy loss.

Oval Window

Upper membrane-covered opening between middle and inner ear supporting the stapes footplate.

Round Window

Lower elastic membrane that moves in opposite phase to oval-window vibrations, allowing cochlear fluid displacement.

Promontory

Bulge of the basal turn of the cochlea that separates the oval and round windows in the middle-ear wall.

Mastoid Bone

Honeycombed portion of temporal bone surrounding the ear; contains air cells and houses the mastoid process used for bone-conduction testing.

Stapedius Muscle

7-mm muscle from posterior wall to stapes neck; CN VII innervation; contraction stiffens ossicular chain, reducing vibration.

Tensor Tympani Muscle

25-mm muscle from medial wall to malleus manubrium; CN V innervation; contraction tenses the tympanic membrane.

Fallopian Canal

Bony channel on middle-ear medial wall that encloses a branch of the facial nerve (CN VII).

Chorda Tympani

Branch of CN VII crossing the middle ear that carries anterior-tongue taste sensation.

Conductive Hearing Loss (CHL)

Hearing reduction caused by pathology of outer or middle ear that impedes sound conduction; bone thresholds remain normal.

Type B Tympanogram

Flat tympanogram indicating minimal eardrum mobility, commonly seen with middle-ear fluid (otitis media).

Type C Tympanogram

Negative-pressure tympanogram with peak at negative pressure, linked to eustachian tube dysfunction or TM retraction.

Eustachian Tube Dysfunction

Failure of tube to open/close properly, causing negative middle-ear pressure, TM retraction, slight CHL, and Type C tympanogram.

Otitis Media (OM)

Inflammation/infection of middle-ear mucosa, often bacterial or viral; most common pediatric middle-ear disorder causing CHL.

Otitis Media with Effusion (OME)

Fluid accumulation in middle ear without acute infection; can cause up to 60 dB CHL and yields Type B tympanogram.

Serous Otitis Media

OME subtype with thin, watery (non-purulent) fluid in the middle ear.

Suppurative (Purulent) Otitis Media

OME subtype where pus fills the middle-ear cavity.

Mucoid ‘Glue’ Ear

OME subtype featuring thick, viscous mucous secretions that coat the middle-ear space.

Acute Otitis Media

Rapid-onset OM lasting 0-21 days with swelling, redness, and pain.

Chronic Otitis Media

Persistent OM exceeding 8 weeks; may erode ossicles and risk mastoiditis.

Myringotomy / Tympanostomy

Surgical incision in the tympanic membrane to relieve pressure or drain fluid.

Pressure-Equalizing (PE) Tube

Small tube inserted into a myringotomy incision to ventilate middle ear and act as an artificial eustachian tube.

Cholesteatoma

Epidermal growth within middle-ear spaces, often following chronic OME; erosive mass causing progressive CHL and requiring surgical removal.

Otosclerosis

Hereditary bony growth around stapes footplate leading to fixation and progressive CHL, often showing Carhart’s notch on audiogram.

Carhart’s Notch

Apparent dip in bone-conduction threshold around 2000 Hz associated with otosclerosis.

Stapedectomy

Surgical removal and prosthetic replacement of the stapes to treat otosclerosis.

Mastoiditis

Bacterial infection of mastoid air cells, usually following unresolved OM; may necessitate mastoidectomy.

Mastoidectomy

Surgical procedure to remove diseased mastoid air cells, often for mastoiditis treatment.

Tympanoplasty

Surgical reconstruction of the tympanic membrane and/or ossicles to restore middle-ear function.

Myringoplasty

Simplest form of tympanoplasty that repairs only the tympanic membrane.

Facial Palsy

Paralysis of one side of the face due to facial-nerve damage; may follow chronic OM erosion of the fallopian canal.

Bell’s Palsy

Idiopathic, flaccid facial paralysis often resolving spontaneously; diagnosis by exclusion.

Patulous Eustachian Tube

Condition where the eustachian tube remains chronically open, producing autophony and head ‘in a barrel’ sensation.