The lesser petrosal grooves are one of the largest and deepest vascular grooves visible on the posterior wall of the middle cranial fossa, just above the level of the foramen magnum petrosal.
Position of the sacral tubercle. The sairacellular tubercle is located in the pyramids of Vileiri at a distance from their apex, approximately 4-5 mm behind the apex of the pyramid. A peculiar pyramidal protrusion outward and upward hangs over the groove of the large petrosal-canine (cochlear) nerve, and below it naturally corresponds to the grooves of the carotid arteries. Posteriorly, the groove of the greater petrosal nerve is completely filled with the cerebellar ganglion and the root of its internal carotid artery. Before the upper limit