Outer & Middle Ear Anatomy and Physiology

Vocabulary-style flashcards covering the key terms and definitions for outer and middle ear anatomy and their primary functions, landmarks, and basic physiology as presented in the notes.

Pinna (auricle)

The visible part of the outer ear that collects sound and helps localize sound in space.

External auditory canal (ear canal)

The canal that funnels sound toward the tympanic membrane; shape is S-shaped; outer third is cartilaginous with hairs and cerumen, inner two-thirds is osseous; contributes to amplification and protection.

Cerumen (earwax)

Wax produced in the outer ear that traps debris and protects the tympanic membrane.

Helix

The upper rim of the pinna.

Antihelix

The inner ridge inside the helix.

Tragus

A small projection at the opening of the ear canal that helps define the ear opening.

Antitragus

The projection opposite the tragus on the outer ear.

Concha

The central bowl portion of the outer ear that helps collect sound.

Lobule (lobe)

The fleshy lower part of the ear; often pierced.

Ear canal shape

The ear canal is generally described as S-shaped to protect the tympanic membrane.

Outer ear function

Primary: amplification (gain) of incoming sound. Secondary: protection from debris via cerumen, hairs, and canal structure.

Resonance and amplification (outer ear)

The geometry of the outer ear boosts certain frequencies, supporting high-frequency speech cues.

Monaural vertical localization

Vertical sound localization that relies on cues from a single ear, shaped by the pinna.

Binaural horizontal localization

Left–right sound localization that relies on differences between the two ears.

Interaural Level Difference (ILD)

Difference in sound intensity between the left and right ears used to localize sound in the horizontal plane.

Interaural Time Difference (ITD)

Difference in arrival time of a sound between the two ears used to localize sound in the horizontal plane.

Tympanic membrane (eardrum)

Cone-shaped boundary between the outer and middle ear that converts air-pressure waves into mechanical vibrations for the ossicles.

Pars tensa

The large, taut part of the tympanic membrane.

Pars flaccida

The small, looser portion of the tympanic membrane near the top.

Malleus

The hammer; the first middle-ear ossicle connected to the tympanic membrane.

Incus

The anvil; the middle-ear ossicle between the malleus and stapes.

Stapes

The stirrup; the smallest middle-ear bone connected to the incus and the oval window.

Eustachian tube

The canal connecting the middle ear to the nasopharynx; functions to equalize pressure and allow drainage.

Valsalva maneuver

Technique to temporarily open the Eustachian tube by pinching the nose and gently blowing with the mouth closed to equalize middle-ear pressure.