Section 230: The mastoid portion (VIIf) of the facial nerve and stylomastoid vein (stv) are still visible on their vertical descent through the temporal bone. The non-sensory portion of the posterior (psc) semicircular canal is in two parts while there is only one cut through the lateral (lsc) semicircular canal. The posterior tip of the short process of the incus (i) is just visible in the fossa incudis. The bony portion of the external auditory meatus (EAM) is located laterally. Note that the horizontal canal is bisected by a line through the facial canal and the posterior canal is bisected by a line through the horizontal canal and points to the endolymphatic sac (es).