[Surgical anatomy of the greater petrosal nerve]

In 40 preparations of mature persons' corpses of both sex by means of the preparation method under binocular microscope MbC-2 under water, surgical anatomy of the geniculate node and the nervus petrosus major has been studied in reference to neurotomy with a transtympanic approach. The geniculate node and the beginning of the n. petrosus major are projected on the angle between the tegmental and labyrinthine walls of the tympanic cavity on the bone part seen from the side of the external auditory meatus between the caput mallei and the tendon of the m. tensor tympani. The projection point is 3.7-5.2 mm forward the inferior edge of the vestibular fenestra and 0-4 mm behind the tympanic opening of the auditory tube. These dimensions depend on the form of the n. facialis geniculum and the temporal bone pyramid, as well as on the size of the tympanic cavity. The thickness of the bone separating the beginning of the n. petrosus major and the tympanic cavity is not more than 1-2 mm.