Branch of the singular nerve (posterior ampullary nerve) in the otic capsule

The frequency of occurrence, location and course of the branch of the singular nerve in the otic capsule in man was investigated by examining the histological sections of 223 human temporal bones. In the proximal portion near the internal auditory meatus the branch of the singular nerve was observed in 194 bones (87%), and was seen to join the main trunk of the singular nerve in 181 of those bones. In the distal portion near the posterior semicircular canal ampulla in 58 bones (26%) and in 45 of those bones it was seen to arise directly from the main trunk of the singular nerve. In 13 bones the branch was seen taking its course in the otic capsule independently from the main trunk all the way to the posterior canal crista. The accessory portion of the branch of the singular nerve reached the dura mater of the posterior cranial fossa near the internal auditory meatus in 11 of 223 bones.