What is the role of the superior canal in the vestibular system?

• A. It senses head rotation in the vertical plane
• B. It provides auditory transduction
• C. It primarily detects linear acceleration
• D. It stabilizes gaze through the optokinetic system

Answer: (B)

The superior canal is one of the semicircular canals that detects angular head motion, specifically rotation in the vertical (sagittal) plane. When you nod or tilt your head, endolymph flow deflects the cupula in this canal, bending hair cells and changing the firing rate of the vestibular nerve to signal rotation about the head’s horizontal axis. This input helps drive the vestibulo-ocular reflex to keep your gaze steady during head movements.

Auditory transduction happens in the cochlea, not the vestibular system. Linear acceleration is detected by the otolith organs (utricle and saccule), not the canals. The visual-vestibular interactions for gaze stabilization involve the vestibulo-ocular reflex and other visual reflexes; describing stabilization strictly as through the optokinetic system isn’t accurate for this canal’s role.