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| Macula of saccule | |
|---|---|
| Details | |
| Identifiers | |
| Latin | macula sacculi |
| TA98 | A15.3.03.084 |
| TA2 | 7002 |
| FMA | 74944 |
| Anatomical terminology | |
Thesaccule is the smaller sizedvestibular sac (theutricle being the other larger size vestibular sac); it is globular in form, and lies in the recessus sphæricus near the opening of thescala vestibuli of thecochlea. Its anterior part exhibits an oval thickening, themacula of saccule (orsaccular macula), to which are distributed the saccular filaments of theacoustic nerve.
The vestibule is a region of the inner ear which contains thesaccule and the utricle, each of which contain a macula to detectlinear acceleration. Its function is to detect vertical linear acceleration.
The macula of saccule lies in a nearly vertical position. It is a 2mm by 3mm patch of hair cells. Each hair cell of the macula contains 40 to 70stereocilia and one truecilia, called akinocilium. A gelatinous cover called theotolithic membrane envelops the tips of the stereocilia and kinocilium. The otolithic membrane is weighted with small densely packedprotein-calcium carbonate granules calledstatoconica.
The macula of the utricle is in a horizontal position and detects horizontal acceleration. The coordinatedsensory perception of acceleration both vertically and horizontally along the vestibular nerve, allow for the perception of linear acceleration in any direction.
In vertical linear acceleration, the weighted otolithic membrane lags behind the stereocilia and kinocilium. This bends the stereocilia, which is interpreted by the brain as vertical linear acceleration.[1][2][3]
This article incorporates text in thepublic domain frompage 1052 of the 20th edition ofGray's Anatomy(1918)
