Areas of Blood Supply
The short branches of the anterior cerebralartery (AB1) extend to the optic chiasm, tothe septum pellucidum, to the rostrum and genu of the corpus callosum, while the long recurrent artery of Heubner (long centralartery) runs to the medial part of the head of the caudate nucleus and to the anterior limb of the internal capsule. The cortical branches supply the medial parts of the base of the frontal brain and the olfactory lobe, and also the frontal and parietal cortex on the medial surface of the hemisphere and the corpus callosum as far as the splenium. The supply area of the artery ex-tends beyond the edge of the pallium to the dorsal convolutions of the convexity.
The striate branches of the middle cerebralartery (AB2) terminate in the globus pal-lidus, in parts of the thalamus, in the genu and parts of the anterior limb of the internal capsule. The branches given off by the insu-lar arteries ramify in the insular cortex and in the claustrum and reach into the external capsule. The area supplied by the cortical branches includes the lateral surface of frontal, parietal, and temporal lobes and also a large part of the central region and the temporal pole. The branches not only supply the cortex but also the white matter as far as the lateral ventricle, including the central part of the optic radiation.
The posterior cerebral artery (AB3) gives off fine short branches that supply the cerebral peduncles, pulvinar, geniculate bodies, quadrigeminal plate, and splenium of the corpus callosum. The cortical supply area occupies the basal part of the temporal lobe and the occipital lobe with the visual cortex (striate area); however, the latter is also reached in the region of the occipital pole by the most inferior branches of the middle cerebral artery.
The recurrent artery of Heubner and the striate branches (D4) of the middle cerebralartery (D5) supply the head of the caudate nucleus, putamen, and internal capsule. The role of the anterior choroidal artery (C6) in the supply of deep structures varies; its branches extend not only to the hippocam-pus and amygdaloid body but also to parts of the pallidum and thalamus. The rostral part of the thalamus receives a branch from the posterior communicating artery (C7), the thalamic branch (C8). The middle and caudal parts of the thalamus are supplied by the basilar artery (C9), from where direct branches (C10) may run to the thalamus. Other fine thalamic branches are given off by the posterior choroidal artery (C11) and the posterior cerebral artery (C12).
Vascularization.The large cerebral vesselslie without exception on the surface of the brain. They give off small arteries and arteri-oles that penetrate vertically into the brain and ramify. The capillary network is very dense in the gray matter but far less so in the white matter.
Clinical Note: Sudden obstruction of an arteryby a thrombus, air bubble, or fat droplet in the bloodstream (embolism) causes the death of brain tissue in the supply area of the affected artery. The anastomoses between the vascular areas are not adequate to supply the affected region through nearby areas in case of a sudden obstruc-tion. Especially affected are the middle cerebralartery and its branches.