Rotational testing assesses function of which vestibular structure?

• A. Otolith organs
• B. Semicircular canals
• C. Auditory system
• D. Visual cortex

Answer: (B)

Rotational testing targets the semicircular canals because these structures detect angular or rotational head movements and drive the vestibulo-ocular reflex that stabilizes gaze during rotation. When you spin, the endolymph inside the canals lags behind the moving head, bending the hair cells in the ampulla and sending signals that produce compensatory eye movements in the opposite direction. This testing specifically probes how well those canals respond during and after rotation. In contrast, the otolith organs sense linear acceleration and head position relative to gravity, not rotation, and the auditory system and visual cortex aren’t responsible for the vestibular reflexes being tested. So the semicircular canals are the part being assessed.