A 28-year-old man develops ipsilateral hyperacusis after parotid surgery. The injured muscle responsible arises from which structure?

• A Processus cochleariformis
• B Petrosquamous plate
• C Promontory of the medial wall
• D Pyramidal eminence ✓

Explanation

The stapedius arises from the pyramidal eminence on the posterior wall of the middle ear, passes forward to insert into the neck of the stapes, and is supplied by the facial nerve. Parotid malignancy or surgery can injure the facial nerve distal to the nerve to stapedius, producing hyperacusis because the damping effect on the stapes is lost. The processus cochleariformis houses the tensor tympani tendon, making option A the tempting distractor.

Reference: Gray's Anatomy, 42nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.