transverse crest of internal acoustic meatus
trans·verse crest of in·ter·nal a·cous·tic me·a·tus[TA]
a horizontal ridge that divides the fundus of the internal acoustic meatus into superior and inferior areas. In the former are the introitus of the facial canal and openings for the branches of the vestibular nerve to the utricle and to the ampullae of the anterior and lateral semicircular canals. In the latter are openings for the cochlear nerve, and for branches of the vestibular nerve to the saccule and to the ampulla of the posterior semicircular canal.