From the posterior wall of the
saccule
The saccule (Latin: sacculus) is a bed of sensory cells in the inner ear that detects linear acceleration and head tilting in the vertical plane, and converts these vibrations into electrical impulses to be interpreted by the brain. When the he ...
a canal, the
endolymphatic duct
From the posterior wall of the saccule a canal, the endolymphatic duct, is given off; this duct is joined by the ductus utriculosaccularis, and then passes along the aquaeductus vestibuli and ends in a blind pouch ( endolymphatic sac) on the pos ...
, is given off; this duct is joined by the
utriculosaccular duct
The utriculosaccular duct is a part of the membranous labyrinth of the inner ear which connects the two parts of the vestibule, the utricle and the saccule. It continues to the endolymphatic duct and ends in the endolymphatic sac.
Importance
T ...
, and then passes along the
vestibular aqueduct
At the posterior lateral wall of the temporal bone is the vestibular aqueduct, which extends to the posterior surface of the petrous portion of the temporal bone. The vestibular aqueduct parallels the petrous apex, in contrast to the cochlear ...
and ends in a blind pouch, the endolymphatic sac, on the posterior surface of the
petrous portion of the
temporal bone
The temporal bone is a paired bone situated at the sides and base of the skull, lateral to the temporal lobe of the cerebral cortex.
The temporal bones are overlaid by the sides of the head known as the temples where four of the cranial bone ...
, where it is in contact with the
dura mater. Studies suggest that the endolymphatic duct and endolymphatic sac perform both absorptive and
secretory
Secretion is the movement of material from one point to another, such as a secreted chemical substance from a cell or gland. In contrast, excretion is the removal of certain substances or waste products from a cell or organism. The classical mec ...
, as well as phagocytic and immunodefensive, functions.
Fittingly,
contrast agent
A contrast agent (or contrast medium) is a substance used to increase the contrast of structures or fluids within the body in medical imaging. Contrast agents absorb or alter external electromagnetism or ultrasound, which is different from radiop ...
uptake in the endolymphatic sac and duct in
MRI
Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and rad ...
is inversely correlated to
endolymphatic hydrops
Endolymphatic hydrops is a disorder of the inner ear. It consists of an excessive build-up of the endolymph fluid, which fills the hearing and balance structures of the inner ear. Endolymph fluid, which is partly regulated by the endolymph sac, ...
,
[J. Gerb, E. Kierig, V. Kirsch, Sandra Becker‐Bense, Rainer Boegle, Thomas Brandt, Marianne Dieterich: ''Contrast Agent Uptake in Endolymphatic Sac and Duct: Inverse Relation to Endolymphatic Hydrops.'' In: ''The Laryngoscope.'' 2025 .] and endolymphatic sac and duct morphology changes have been observed in
Meniere's Disease.
[David Bächinger, Ngoc-Nhi Luu, Judith Kempfle, Samuel R. Barber, Daniel Zürrer, Daniel J. Lee, Hugh D. Curtin, Steven D. Rauch, Joseph B. Nadol, Joe C. Adams, Andreas H. Eckhard: ''Vestibular Aqueduct Morphology Correlates With Endolymphatic Sac Pathologies in Menière's Disease—A Correlative Histology and Computed Tomography Study.'' In: ''Otology & Neurotology.'' 2019, Band 40, Nummer 5, S. e548–e555 .]
Neoplasms of the endolymphatic sac are very rare tumors.
References
External links
Images at wustl.edu
Vestibular system
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