Fig. 1

Different anatomic regions of the thalamus and its arterial supply. AOP is a solitary arterial trunk of bilateral thalamo-perforating artery originated from P1 segment of one of PCA, which supplies bilaterally the paramedian thalamic territories (A). When the polar artery is absent, AOP not only may supply the paramedian but also the anterior thalamic territories (B). The rostral midbrain has supplied by the superior mesencephalic artery, which share a common origin with AOP (C). The red nucleus has supplied by the rubral artery, which share a common origin with AOP (D). AOP, artery of percheron; PCA, posterior choroidal artery; BA, basilar artery; AN, anterior nucleus; LN, lateral nuclei; MDN, mediodorsal nuclei; PUL, pulvinar; RN, red nucleus