Internal carotid artery.

A. carotis interna, the internal carotid artery, starting from the common carotid artery, rises to the base of the skull and enters the canalis caroticus of the temporal bone. In the neck it does not give branches; at the very beginning lies outwards from a. carotis externa, respectively, the development of the lateral trunk of the dorsal aorta, but soon begins to go to the medial surface of the latter. According to the curvature of canalis caroticus, the internal carotid artery, passing first vertically in it, then bends in the anteromedial direction and, at the apex of the temporal bone, enters the cranial cavity through the foramen lacerum; curving upward, it rises along the sulcus caroticus of the sphenoid bone, turns back forward at the bottom of the Turkish saddle, passes through the thickness of the cavernous sinus, and in the canalis opticus makes the last bend upwards and backwards, giving its first branch, a. ophthalmica, after which it pierces the hard and spider shells and, finally, is divided into its final branches.