Etude anatomo-histologique de l’anastomose vestibulo-cochléaire de Von Oort

Abstract

The vestibulocochlear anastomosis was first described in 1918 by von Oort. It is situated deeply at the bottom of the internal acoustic meatus, and spreads from the saccular nerve before its terminal ramifications, to the cochlear nerve before its penetration into the cochlea. Nerve fibers of the cochlear efferent system are thought to pass through it. The aim of our study was to investigate the anatomy of the vestibulocochlear anastomosis and characterize its histological features. [corrected] Ten human temporal bones were dissected. Serial sections were obtained for histological evaluation. The vestibulocochlear anastomosis was found in seven of the specimens, perfectly visualized in six. Average diameter was 0.5 mm with lengths varying from 0.5 to 1 mm. Serial histological sections demonstrated the nervous nature of the anastomosis and its relations with the saccular and cochlear nerves. The epinevrium of the saccular nerve was continuous with the supposed anastomosis in five of the specimens, demonstrating the distinct nature of the anastomosis from the saccular and cochlear nerves. We did not find any evidence linking these fibers to the cochlear efferent system. The vestibulocochlear anastomosis was found in seven of our ten dissections. The anastomosis is probably an anatomic reality composed of nerve fibers. The efferent function of these fibers remains to be demonstrated.