THE NEUROVASCULAR RELATIONSHIPS AND THE BLOOD-SUPPLY OF THE OCULOMOTOR NERVE - THE MICROSURGICAL ANATOMY OF ITS CISTERNAL SEGMENT

The 27 oculomotor nerves were examined after injection of India ink or methylmethacrylate into the vertebral and the internal carotid arteri es. The ventral surface of the cisternal segment of the nerve was note d to be in close relationship with the superior cerebellar artery (96. 3%) and its pontine (37.0%), mesencephalic (25.9%) and perforating bra nches (81.5%); the posterolateral pontine artery (70.4%) and its branc hes; the anterolateral pontine branches (29.6%) and the perforating br anches (85.2%) of the basilar artery; the mesencephalic perforating ar teries (11.1%) and their peduncular branches (62.9%); the peduncular b ranches of the diencephalic perforators (11.1%) and the P1 segment (18 .5%); and the accessory collicular artery (3.7%). The dorsal surface o f the nerve was in close relationships to the P1 and P2A segments (100 %) of the posterior cerebral artery and their peduncular branches (22. 2%); the posterior communicating artery (100%); the collicular (100%) acid the accessory collicular artery (33.3%), and their peduncular (51 .8%) or the perforating branches (22.2%); the medial posterior choroid al artery (25.9%) and its branches (11.1%); and the mesencephalic and diencephalic perforating arteries (100%). Vascular penetration was not ed in 51.8% of the third nerves. The most common penetrating vessel wa s the collicular artery (18.5%) and its branches (22.2%). The cisterna l segment of the oculomotor nerve was most often supplied bp the mesen cephalic perforators (88.9%). The authors discuss the possible clinica l significance of the obtained anatomic data.