Endolymphatic sac

{{Short description|Blind pouch}}

{{Infobox anatomy

| Name = Endolymphatic sac

| Latin = saccus endolymphaticus

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From the posterior wall of the saccule a canal, the endolymphatic duct, is given off; this duct is joined by the utriculosaccular duct, and then passes along the vestibular aqueduct and ends in a blind pouch, the endolymphatic sac, on the posterior surface of the petrous portion of the temporal bone, where it is in contact with the dura mater. Studies suggest that the endolymphatic duct and endolymphatic sac perform both absorptive and secretory,Schuknecht HF. Pathology of the Ear. Philadelphia, Pa: Lea & Febiger; 1993:45–47, 50–51, 62, 64, 101{{Cite journal |last=Wackym |first=P. A. |last2=Friberg |first2=U. |last3=Bagger-Sjöbäck |first3=D. |last4=Linthicum |first4=F. H. |last5=Friedmann |first5=I. |last6=Rask-Andersen |first6=H. |date=August 1987 |title=Human endolymphatic sac: possible mechanisms of pressure regulation |url=https://pubmed.ncbi.nlm.nih.gov/3655528/ |journal=The Journal of Laryngology and Otology |volume=101 |issue=8 |pages=768–779 |doi=10.1017/s0022215100102713 |issn=0022-2151 |pmid=3655528}}{{Cite journal |last=Yeo |first=S. W. |last2=Gottschlich |first2=S. |last3=Harris |first3=J. P. |last4=Keithley |first4=E. M. |date=June 1995 |title=Antigen diffusion from the perilymphatic space of the cochlea |url=https://pubmed.ncbi.nlm.nih.gov/7769947/ |journal=The Laryngoscope |volume=105 |issue=6 |pages=623–628 |doi=10.1288/00005537-199506000-00012 |issn=0023-852X |pmid=7769947}}{{Cite journal |last=Rask-Andersen |first=H. |last2=Danckwardt-Lillieström |first2=N. |last3=Linthicum |first3=F. H. |last4=House |first4=W. F. |date=February 1991 |title=Ultrastructural evidence of a merocrine secretion in the human endolymphatic sac |url=https://pubmed.ncbi.nlm.nih.gov/1992902/ |journal=The Annals of Otology, Rhinology, and Laryngology |volume=100 |issue=2 |pages=148–156 |doi=10.1177/000348949110000211 |issn=0003-4894 |pmid=1992902}} as well as phagocytic{{Cite journal |last=Fukazawa |first=K. |last2=Sakagami |first2=M. |last3=Matsunaga |first3=T. |last4=Fujita |first4=H. |date=July 1991 |title=Endocytotic activity of the free floating cells and epithelial cells in the endolymphatic sac: an electron microscopic study |url=https://pubmed.ncbi.nlm.nih.gov/1867416/ |journal=The Anatomical Record |volume=230 |issue=3 |pages=425–433 |doi=10.1002/ar.1092300315 |issn=0003-276X |pmid=1867416}} and immunodefensive, functions.{{Cite journal |last=Wackym |first=P. A. |last2=Friberg |first2=U. |last3=Linthicum |first3=F. H. |last4=Bagger-Sjöbäck |first4=D. |last5=Bui |first5=H. T. |last6=Hofman |first6=F. |last7=Rask-Andersen |first7=H. |date=May–June 1987 |title=Human endolymphatic sac: morphologic evidence of immunologic function |url=https://pubmed.ncbi.nlm.nih.gov/3300505/ |journal=The Annals of Otology, Rhinology, and Laryngology |volume=96 |issue=3 Pt 1 |pages=276–281 |doi=10.1177/000348948709600308 |issn=0003-4894 |pmid=3300505}} Fittingly, contrast agent uptake in the endolymphatic sac and duct in MRI is inversely correlated to endolymphatic hydrops,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 {{DOI|10.1002/lary.32127}}. 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 {{DOI|10.1097/MAO.0000000000002198}}.

Neoplasms of the endolymphatic sac are very rare tumors.