Section 101: The chorda tympani (ct) appears in two parts. This section is inferior to the bulk of the short process of the incus (si). The internal auditory meatus (IAM) is open to the posterior cranial fossa and contains the superior division (sd) of the eighth cranial nerve. The utricular macula (mu), one of two gravity receptors, is visible in the center, along with cuts through the non-sensory portions of the lateral (lsc), posterior (psc) and superior (ssc) semicircular canals. * - Prussak's space; nr- notch of Rivinus (i.e., incisura tympanica). VIId - Tympanic segment of facial nerve.
Surgical perspective - Note that the superior division of the VIII nerve (sd) enters the end organs (i.e., horizontal and superior cristae & utricular macula) from an anterolateral direction.