Anatomy of the thalamoperforating arteries with special emphasis on arteriography of the third ventricle: Part I.

The thalamoperforating arteries are divided into 2 distinct groups, an anterior and a posterior. The PTPAS are retromammillary branches of the precommunicating segments of the posterior cerebral arteries. The PTPAS may be divided into interpeduncular, mesencephalic and thalamic segments and are not directly related to the third ventricle. They are primarily midbrain and thalamic arteries. The main trunk of the PTPA (mesencephalic segment) normally does not undulate, but assumes a characteristically straight configuration. The ATPAS arise from the posterior communicating arteries anterior and lateral to the mamillary bodies. The ATPAS are primarily diencephalic vessels. Interpeduncular, paraventricular (hypothalamic) and thalamic segments may be identified. The major segment of the ATPAS is para third ventricular in location at the level of the massa intermedia.