Physiological importance of the conjugation of the internal carotid artery and cavernous sinus.

The author considers of utmost importance the anatomical arterial-venous conjugation represented by the internal carotid artery and the cavernous sinus, as well as the carotid venous plexus which covers the internal carotid artery within the petrous portion of the temporal bone. He believes that besides protecting the vascular arterial wall in acute episodes of hypertension, it can also contribute to the mechanism of carotid blood flow. This hypothesis is based on consideration of the physiological conditions of the cavernous sinus in relation to those of other dural venous sinuses, and of the endocranial venous system and its cavernous constitution, which differs from other venous blood canals, which have their own venous physiology and different functions. He attempts to compare it with the rest of the body areas where cavernous plexuses are located and where venous pressure reaches high values, and with other regions without this morphologic constitution. He establishes a correlation resulting from a cerebrovascular resistance mechanism, the participation of which he considers to differ from those of other dural sinuses and encephalic veins. He also emphasizes physiologically the carotid siphon and believes that its participation in the hemodynamics of a hypotensive patient who is lying down, facilitates blood access to the brain, thus avoiding anoxia and brain damage, within certain limits, and constitutes an additional means of body defense.