The petrosal nerve (stony part) in size and location in the cavities of the pyramids of the temporal bone occupies an intermediate position between the nerves of the middle ear and the lower spinous petrosal nerve. At the lower end of the pyramids, just above the plate of the petrous part of the temporal bone, a nerve arises from the inferior petrosal sinus, which further divides into four branches: one along the outer surface of the pyramids - the terminal and superficial petrosal branches, and the other - the connecting branch. The deep petrosal branch continues to the internal auditory canal and divides the pyramid of the temporal bone into two independent formations, the pyramids of the air passage in the pikas of the facial nerve and the internal articular process of the facial bone in the form of a lobe. The stony part, together with the three main branches, forms a pyramidal canal. The last lower branch of the petrous bone - the facial or terminal petrosal - is connected to the lower part of the petrotympanic fissure based on the articulation with the petromastoid joint of the opposite side.