[Microsurgical anatomy of the perforating arteries on the third ventricular floor].

Objective: To study the microvascular anatomy of the perforating arteries on the third ventricular floor.
Methods: The microanatomy of perforating arteries on the third ventricular floor in 25 cadaveric heads of adults was observed with 4 to 40-power surgical microscope.
Results: The perforating arteries on the third ventricular floor arose from the internal carotid, posterior communicating, posterior cerebral and basilar arteries, and could be divided into three patterns: no ramification, proximal ramification, and distal ramification, according to their vascular origin and course. The perforating arteries of proximal ramification pattern had larger diameter and broader distribution These perforating arteries terminated at relative distant area, including a) anterior part: the optic chiasm and stalk and infundibulum; b) middle part: mamillary body and tuber cinereum; c) posterior part: posterior perforated substance and posterior fossa; and d) lateral part: paramedian perforated substance and anterior portion of optic tract. In middle part overlap and anastosis of perforating artery with posterior communicating artery from both sides were relatively few.
Conclusion: The perforating arteries on the third ventricular floor can be divided into three patterns. The proximal ramification pattern possesses larger diameter of the vessel and broader blood supply area on the third ventricular floor. Identification and preservation of these perforating arteries are important when surgery is being planed.