part of part of conduit for vestibular aqueduct http://upload.wikimedia.org/wikipedia/commons/1/16/Gray921.png MESH:D014723 GAID:885 FMA:77821 Wikipedia:Vestibular_aqueduct MA:0001186 At the hinder part of the medial wall of the vestibule is the orifice of the vestibular aqueduct, which extends to the posterior surface of the petrous portion of the temporal bone. It transmits a small vein, and contains a tubular prolongation of the membranous labyrinth, the ductus endolymphaticus, which ends in a cul-de-sac between the layers of the dura mater within the cranial cavity. [WP,unvetted]. aqueductus vestibuli UBERON:0002279 osseus labyrinth vestibule foramen of skull vein of vestibular aqueduct