The organ of Corti rests on the basilar membrane of the cochlea. According to the 'place theory' of hearing, high-frequency sounds stimulate which region of the basilar membrane?

• A Apical (helicotrema) end — wide and loose, resonates at low frequency
• B Middle turns — respond uniformly to all frequencies
• C Basal end (near oval window) — narrow and stiff, resonates at high frequency ✓
• D Throughout the full length uniformly, regardless of frequency

Explanation

According to von Bekesy's place (tonotopic) theory, the basilar membrane has graded mechanical properties: narrow and stiff at the base (near the oval/round window), and wide and flaccid at the apex (helicotrema). High-frequency sounds (>4000 Hz) produce maximal displacement of the basal basilar membrane; low-frequency sounds (<1000 Hz) travel to the apex for maximal displacement. This tonotopic organization is preserved from the cochlea through the auditory cortex (Heschl's gyrus, superior temporal plane). In noise-induced hearing loss, the 4000 Hz notch occurs because the basal region (high-frequency area) is most exposed.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.