The superior cerebellar peduncles (brachia conjunctiva), two in number, emerge from the upper and medial part of the white matter of the hemispheres and are placed under cover of the upper part of the cerebellum.
They are joined to each other across the middle line by the anterior medullary velum, and can be followed upward as far as the inferior colliculi, under which they disappear.
Below, they form the upper lateral boundaries of the fourth ventricle, but as they ascend they converge on the dorsal aspect of the ventricle and thus assist in roofing it in.
The ventral spinocerebellar tract enters the cerebellum through the superior cerebellar peduncles, which otherwise mostly contain efferent fibres.