[The basilar artery of humans]

The basilar artery in 44.4% of the cases came into being by joint of two vertebral arteries on the height of the inferior margin of the pont. However, in 40.4%--below, and in 15.1%--above of this margin. In 78.7% of the human the course of basilar artery was rectilinear. In 20.5% of the cases the bulge of this artery was observed on the right or left side, whereas in 0.8%--the S-shaped forms. In 56% of the persons the segmentation of the basilar artery on the posterior cerebral arteries takes place on the height of the superior margin of the pont, in 32.9%--above, and in 11.1%--below this one. The results of the investigations concerning the place of genesis, the height of segmentation and the direction of course of the particular artery, were permitted on separation of nine types of these blood vessels. The diameter of the initial and terminal section of the basilar artery at the new-born children was--respectively--1.9 and 1.8 mm, whereas at the adult persons it exceeded 4 mm. The length of this vessel ranged from 17.2 mm in the above-mentioned children to approximately 33 mm in persons over 20 years old. In all the examined cases the basilar artery was passing the arteries of the pont: medial and lateral and almost always the superior and the inferior anterior cerebellar arteries. In 12.4% of the persons the inferior posterior cerebellar arteries and, moreover, in 22.2%--the labyrinth arteries were beginning from this blood vessel.