Comparative anatomy of arterial vascularization of the rhinencephalon in man, cat and sheep.

The aim of this study was anatomical and comparative examination of arterial vascularization of the rhinencephalon in man and in macrosmatic mammals. The studies were performed by the own injection method on 27 human brains and 27 animal ones. The cerebral arteries were injected with synthetic colored latex and then prepared in an operating microscope. It was found, that the structure, topography and vascular areas of arteries supplying the rhinencephalon in man and animals are different. Contrary to the human rhinencephalon, strongly developed rhinencephalon in cat and sheep possess its own separate arterial pattern composed of special arteries for each regions of paleocortex, supplying the olfactory bulb and lobe. In the cat and sheep brains, the region corresponding to the human anterior perforated substance comprises the greater rhinencephalon surface. It includes the olfactory tubercle and sulcus between the olfactory and pyriform lobes. Extracerebral segments of the internal arterioles of the anterior and middle cerebral arteries in man and animals have different topography and courses. In the human brain, the studied arterioles originate from the maternal arteries with singular trunks or vascular pedicles and then enter directly the anterior perforated substance. In the cat and sheep brain they derive in two forms: as trunks divided into cortical branches of the olfactory lobe running on the olfactory tubercle surface and penetrating it, as well as singular trunks that enter the brain just over the maternal arteries. In contrary to the extracerebral segments of the anterior perforating arteries in man, analogical arterioles in the cat and sheep brains form numerous anastomoses. Thus, they create anatomical conditions for collateral circulation.