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Abstract

The brains from 14 adult common tree shrews (Tupaia glis) of both sexes were used for the study of hypothalamic blood supply. It is found that the hypothalamus is supplied by branches of arteries that form the circle of Willis. The preoptic region of the anterior hypothalamus is supplied by branches of anterior cerebral and anterior communicating arteries, while branches of the ophthalmic, anterior communicating and superior hypophysial arteries contribute blood to the optic chiasma. The infundibulum and the median eminence receive arterial supply from the circuminfundibular anastomosis deriving from superior hypophysial, posterior communicating as well as from tiny branches of ophthalmic arteries. The blood supply of the mammillary body comes from the posterior cerebral, posterior communicating and terminal part of basilar arteries. The venous blood from the circuminfundibular area is collected into 15 to 20 hypophysial portal veins flowing towards the par distalis of the pituitary gland. The veins from the tuberal and anterior mammillary regions drain into the premammillary vein while the postmammillary vein receives blood from postmammillary region. The premammillary and postmammillary veins drain into the network of venules forming by anterior cerebral and anterior communicating veins which run across the optic chiasma to join the basal vein on each side of interpeduncular fossa. They finally drain into the cavernous sinus and superior petrosal sinus.