Control and autoregulation of the blood circulation in the vertebrobasilar system.

The author establishes an analogy between the control mechanism and autoregulation of the cerebral blood flow and the protection of the vascular wall of the internal carotid artery constituted by the conjunction of the 'internal carotid-cavernous sinus' system with the 'vertebrobasilar-transverse-occipital dural sinus or basilar' 'sinus' system (an extension of the cavernous sinus) in the autoregulation and control of the encephalic circulation carried out through this latter vessel, together with the protection of its vascular walls. The author believes it to be very difficult to demonstrate in practice the functioning of these mechanisms, but he argues that the unusual anatomical features of the systems are indicative of their particular physiological roles.