[1] On the dorsal surface of its lower half the folia and lingula are prolonged.

It forms, together with the superior cerebellar peduncle,[contradictory] the roof of the upper part of the fourth ventricle; it is narrow above, where it passes beneath the facial colliculi, and broader below, where it is continuous with the white substance of the superior vermis.

A slightly elevated ridge, the frenulum veli, descends upon its upper part from between the inferior colliculi, and on either side of this the trochlear nerve emerges.

Blood is supplied by branches from the superior cerebellar artery.

This article incorporates text in the public domain from page 793 of the 20th edition of Gray's Anatomy (1918)