hiatus for lesser petrosal nerve hiatus for lesser petrosal nerve the hiatus for lesser petrosal nerve is a hiatus in the petrous part of the temporal bone which transmits the lesser petrosal nerve. it is located posterior to the groove for the superior petrosal sinus and posterolateral to the jugular foramen. hiatus for lesser petrosal nervemandibular division of trifacial nerve, seen from the middle line. the small figure is an enlarged view of the otic ganglion.the course and connections of the facial nerve in the temporal bone.detailsidentifierslatinhiatus canalis nervi petrosi minorista98a02.1.06.026ta2664fma56448anatomical terminology the hiatus for lesser petrosal nerve receives the lesser petrosal nerve as it branches from the glossopharyngeal nerve (cn ix) before the glossopharyngeal enters the posterior cranial fossa through the jugular foramen. the lesser petrosal nerve then travels anteriorly from the hiatus toward the foramen ovale, through which it exits the cranial cavity.