Which structure anchors the lateral margin of the tectorial membrane, allowing shearing forces to develop between it and the organ of Corti during basilar membrane displacement?
- A Basilar membrane at the spiral ligament
- B Spiral limbus ✓
- C Osseous spiral lamina
- D Stria vascularis
Correct answer: B. Spiral limbus
Explanation
The tectorial membrane arises from and is anchored to the vestibular lip of the spiral limbus on the osseous spiral lamina. Because its outer edge floats free over the hair cell stereocilia, upward deflection of the basilar membrane creates shear between the tectorial membrane and the reticular lamina, deflecting stereocilia. The stria vascularis lies on the outer wall of the scala media and has no tectorial attachment.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.