It forms, together with the superior cerebellar peduncle, 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.
Blood is supplied by branches from the superior cerebellar artery.
Scheme of roof of fourth ventricle. 1. Posterior medullary velum 2. Choroid plexus 3. Cisterna cerebellomedullaris of subarachnoid cavity 4. Central canal 5. Corpora quadrigemina 6. Cerebral peduncle 7. Anterior medullary velum 8. Ependymal lining of ventricle 9. Cisterna pontis of subarachnoid cavity (Arrow = Flow of cerebrospinal fluid (CSF) through foramen of Magendie)
Mesal aspect of a brain sectioned in the median sagittal plane.