Microsurgical anatomy of the superior cerebellar artery.

Fifty cerebellar hemispheres from 25 adult cadavers were examined. The superior cerebellar artery (SCA) was present in each of the 50 hemispheres. Forty-three SCAs arose as a single trunk, and 7 arose as duplicate trunks. One solitary trunk and the rostral trunk of one duplicate vessel arose from the posterior cerebral artery. The remainder arose from the basilar artery. The SCA was divided into four segments: the anterior pontomesencephalic segment lay below the oculomotor nerve; the lateral pontomesencephalic segment course; below the trochlear and above the trigeminal nerve; the cerebellomesencephalic segment coursed in the groove between the cerebellum and the upper brain stem; and the cortical segment was distributed to the cerebellar surface. The SCAs arising as a single trunk bifurcated into a rostral and a caudal trunk, corresponding to the runks formed by a duplicate origin. The rostral trunk supplied the medial and the caudal trunk supplied the lateral parts of the cerebellar cortex. The SCA gave off perforating, precerebellar, and cortical arteries. The perforating arteries penetrated the interpeduncular fossa, the cerebral peduncles, the junctions of the superior and middle cerebellar peduncles, and the colliculi. The precerebellar branches arose within the cerebellomesencephalic groove and supplied the adjoining parts of the cerebellum and brain stem. The cortical branches were divided into vermian, hemispheric, and marginal arteries. The 50 SACs had points of contact with 32 oculomotor, 46 trochlear, and 26 trigeminal nerves. (Neurosurgery, 6: 10--28, 1980)