BENDS OF THE INTERNAL CAROTID ARTERY, FUNCTIONAL GEOMETRY

Abstract

The interesting phenomenon exists in cerebral blood circulation that unites two simultaneous, interconnected processes: a) In cerebral arteries, distal to the bends of cranial internal carotid artery (ICA), the blood flow pulse pressure is significantly lower than in other extracranial arteries of similar caliber (damping of arterial pulse pressure); b) In a pulsatile manner accelerated blood flows from the cerebral venous system into the jugular vein and at the same time it pulsates in synchrony with the pulsation of the internal carotid artery.

The aim of the present work is to investigate the anatomical basis of the above-mentioned phenomenon, in particular, its connection with the cranial part of the internal carotid artery. The study was conducted on 34 canine cerebral vascular preparations, which were prepared by injecting the cerebral blood vessels with a blood vessel-hardening masses and using a subsequent corrosion technique.

The study revealed that the bends of the internal carotid artery of the cranial part, significantly elongate the artery which is surrounded by venous formations and is located in a limited space created for it by bone and dural membranes at the base of the skull. This limited space provides effective damping of pulse pressure and pulsatile acceleration of blood expulsion from the cerebral venous system into the jugular veins. Since the development of this phenomenon requires not point-like but rather “large-area” interaction between the artery and venous structures, arterial bends appear to be one of the most optimal options for expanding this interaction. The phenomenon of damped arterial blood supply to the brain and simultaneous pulsatile acceleration of cerebral venous blood outflow from the cranial cavity associated with the pulsation of the internal carotid artery, may be the basis for the formation of bends of the intracranial internal carotid artery.