3 segments (named for surrounding cistern) and their branches:
a) peduncular segment (P1)
● mesencephalic perforating aa. (⇒ tectum, cerebral peduncles, and these nuclei: Edinger- Westphal, oculomotor and trochlear)
● interpeduncular thalamoperforators (1st of 2 groups of posterior thalamoperforating aa.)
● medial post. choroidal (most from P1 or P2)
b) ambient segment(P2)
● lateral post. choroidal (most from P2)
● thalamogeniculate thalamoperforators (2nd of 2 groups of posterior thalamoperforating aa.) ⇒ geniculate bodies + pulvinar
● anterior temporal (anastamoses with anterior temporal br. of MCA)
● posterior temporal
● parieto-occipital
● calcarine
c) quadrigeminal segment (P3)
● quadrigeminal & geniculate branches ⇒ quadrigeminal plate
● post. pericallosal (splenial) (anastomoses with pericallosal of ACA)