A patient with benign paroxysmal positional vertigo has otoconia displaced from the utricular macula. In which anatomical plane does the macula of the utricle lie, and how does this differ from the saccular macula?

• A Utricle horizontal, saccule vertical ✓
• B Utricle vertical, saccule horizontal
• C Both lie in the horizontal plane
• D Utricle oblique at 45 degrees, saccule horizontal

Explanation

The utricular macula lies predominantly in the horizontal plane on the floor of the utricle, detecting linear acceleration in the horizontal direction and static head tilt. The saccular macula lies vertically on the medial wall of the saccule, sensing linear acceleration in the vertical plane. This orthogonal arrangement explains why posterior canal BPPV is provoked by head-hanging positions that excite the horizontally oriented utricle.

Reference: Gray's Anatomy: The Anatomical Basis of Clinical Practice, 42nd ed.

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Written and medically reviewed by the StethoPrep medical team.