Section 532: The ampulla/crista of the superior semicircular canal (asc) is visible near the utricular macula (mu). The round window membrane (rw) separates scala tympani from the middle ear. The promontory (p) makes a bulge on the medial wall of the middle ear space. The endolymphatic duct (ed) is just entering the vestibule. The tympanic membrane has been artifactually ruptured. VIId - Tympanic segment of facial nerve.