Utriculosaccular duct
{{Short description|Part of the inner ear}}
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.{{Cite journal |last1=Mazan |first1=Sylvie |last2=Jaillard |first2=Danielle |last3=Baratte |first3=Blandine |last4=Janvier |first4=Philippe |date=July 2000 |title=Otx1 gene-controlled morphogenesis of the horizontal semicircular canal and the origin of the gnathostome characteristics |url=https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1525-142x.2000.00062.x |journal=Evolution & Development |volume=2 |issue=4 |pages=186–193 |doi=10.1046/j.1525-142x.2000.00062.x |pmid=11252561 |issn=1520-541X}} It continues to the endolymphatic duct and ends in the endolymphatic sac.
Importance
This structure plays an important role as a duct that serves as a conduit for endolymph between these structures, maintaining proper fluid dynamics essential for vestibular function. Specifically because the utriculosaccular duct carries the endolymphatic fluid to the endolymphatic sac, where it is drained. This system of the endolymphatic fluid prevents excessive fluid build-up in the inner ear, a condition also known as endolymphatic hydrops, which is associated with Ménière´s disease{{Cite journal |last1=Salt |first1=Alec N. |last2=Plontke |first2=Stefan K. |date=October 2010 |title=Endolymphatic hydrops: pathophysiology and experimental models |journal=Otolaryngologic Clinics of North America |volume=43 |issue=5 |pages=971–983 |doi=10.1016/j.otc.2010.05.007 |issn=1557-8259 |pmc=2923478 |pmid=20713237}} and others vestibular disorders.{{Cite journal |last1=Oh |first1=Sun-Young |last2=Dieterich |first2=Marianne |last3=Lee |first3=Bit Na |last4=Boegle |first4=Rainer |last5=Kang |first5=Jin-Ju |last6=Lee |first6=Na-Ri |last7=Gerb |first7=Johannes |last8=Hwang |first8=Seung-Bae |last9=Kirsch |first9=Valerie |date=2021 |title=Endolymphatic Hydrops in Patients With Vestibular Migraine and Concurrent Meniere's Disease |journal=Frontiers in Neurology |volume=12 |pages=594481 |doi=10.3389/fneur.2021.594481 |doi-access=free |issn=1664-2295 |pmc=7991602 |pmid=33776877}} Further evidence for this physiological drainage mechanism can be seen in contrast-enhanced inner ear MRI, where the post-contrast visibility of endolymphatic sac and duct is inversely correlated to the amount of endolymphatic hydrops, independent of clinical diagnosis.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}}.