The Superior Cerebellar Artery: An Anatomic-Roentgenographic Correlation

THE INDICATIONS for vertebral arteriography have expanded with the increased use of selective catheter technics. The evaluation of these studies depends on a knowledge of the normal gross and roentgenologic anatomy of the posterior fossa vasculature. A detailed anatomic and roentgen analysis of many of these infratentorial arteries and veins has appeared in the recent literature (1–7, 9). A precise description with correlation of the normal anatomy of the superior cerebellar artery, however, has not been published. In this communication we describe the normal course and distribution of the superior cerebellar artery in anatomic specimens as well as in clinical material. Material and Method The anatomic information was derived from two sources. One was the gross material represented by 30 brains from cadavers. The superior cerebellar arteries were filled with a Micropaque-gel suspension after injection of one of the vertebral arteries. After fixation, the specimens were dissected and photographed to establish the normal gross relationship of the superior cerebellar artery to adjacent structures. Roentgenograms of the specimens were then obtained, and roentgenographic and gross anatomy correlated. The other source was roentgenographic material consisting of normal vertebral arteriograms of 100 patients. All studies were performed by selective catheterization of the vertebral artery via the femoral or, less frequently, the axillary routes. In all instances standard half-axial and lateral projections were obtained, supplemented by anteroposterior projections in 20 patients. Stereoscopic lateral projections were obtained in 5 patients. Anatomic Description Gross Anatomy: The superior cerebellar arteries are the most rostral pair of infratentorial vessels, originating from the basilar artery. The proximal trunk of the superior cerebellar artery courses posteriorly around the midbrain to supply the tectum, the superior surface of the cerebellar hemispheres, and the superior vermis. In the perimesencephalic cisterns, it may be divided into 3 main parts : interpeduncular-crural, ambient, and quadrigeminal. From its origin in the interpeduncular cistern, the first segment of the superior cerebellar artery (interpeduncular-crural) takes a lateral course from the basilar artery to reach the anterolateral portion of the brain stem (Fig. 1). Here it lies inferior to the emerging rootlets of the oculomotor nerve, which separates it from the proximal segment of the posterior cerebral artery. As it continues anterolaterally around the peduncle, it traverses the crural cistern. The second portion (ambient) of the superior cerebellar artery passes posteriorly through the ambient cisterns. This portion of the artery is related to the midbrain medially, to the superior cerebellar peduncle inferiorly, and to an overlapping cuff of cerebellum laterally (Fig. 2).