THE SUSPENSORY LIGAMENT OF THE ENDOLYMPHATIC DUCT IN THE RAT - AN ULTRASTRUCTURAL-STUDY

Following optimized fixation and specimen handling, the endolymphatic duct was investigated by transmission and scanning electron microscopy . Tubular microfibrils, 10-12 nm thick and of indefinite length, occup ied the subepithelial compartment abundantly and seemed to insert into the basal lamina of the epithelial cells of the duct and to merge wit h the bony wall of vestibular aqueduct thus forming a suspensory ligam ent of the endolymphatic duct. This ligament is suggested to protect t he endolymphtaic duct from collapsing and to play a role in the mechan ical protection of the vestibular apparatus from sudden increases in i ntracranial pressure. The capillaries and the aqueductal vein were loc ated in intimate relationship to the epithelial cells. Both types of v essels were provided with fenestrations of the endothelial cells, supp orting the proposal that the endolymphatic duct may be involved in the resorption of endolymph.