Cerebellar peduncles connect the cerebellum to the brain stem. There are six cerebellar peduncles in total, three on each side:

• Superior cerebellar peduncle is a paired structure of white matter that connects the cerebellum to the mid-brain.
• Middle cerebellar peduncles connect the cerebellum to the pons and are composed entirely of centripetal fibers.
• Inferior cerebellar peduncle is a thick rope-like strand that occupies the upper part of the posterior district of the medulla oblongata.

The peduncles form the lateral border of the fourth ventricle, and form a distinctive diamond – the middle peduncle forming the central corners of the diamond, while the superior and inferior peduncles form the superior and inferior edges, respectively.