AAO-HNSF Certificate Program for Otolaryngology Personnel

The External Ear Canal

•Skin over cartilaginous portion is thick and adherent

•Skin over bony canal is thin, sensitive to palpation and susceptible to trauma

AAO-HNS/F

Certificate Program for Otolaryngology Personnel Workshop

7

Function of the EAC

• Small role in sound amplification • Protects the tympanic membrane from injury: • Curved shape prevents direct entry Hair and cerumen trap foreign bodies (including bugs) • Epithelial migration makes the normal ear canal self-cleaning

AAO-HNS/F

Certificate Program for Otolaryngology Personnel Workshop

8

The Middle Ear

• Space bounded by the tympanic membrane and promontory • Contains ossicles (malleus, incus, stapes) • Access to cochlea (oval, round windows) • Eustachian tube anteriorly ventilates space

AAO-HNS/F

Certificate Program for Otolaryngology Personnel Workshop

9