Cerebellum

The cerebellum is the dorsal part of the metencephalon located caudal to the cerebrum and dorsal to the pons and medulla oblongata. It lies within the caudal cranial fossa and is separated from the cerebrum by the transverse fissure. The cerebellum forms the dorsal boundary of the fourth ventricle and is connected to the brainstem through the cerebellar peduncles.

Structurally, the cerebellum consists of a median vermis and two cerebellar hemispheres. Its surface is divided into numerous narrow transverse folds called folia, which are separated by fissures. Several lobules and fissures are recognized, including the lingula, culmen, declive, folium vermis, tuber vermis, pyramis vermis, uvula vermis, and nodulus.

The cerebellum contains an outer cortex composed of gray matter and an internal medullary substance formed by white matter. It maintains extensive connections with the brainstem through afferent and efferent pathways traveling in the cerebellar peduncles.

Functionally, the cerebellum is involved in the coordination and regulation of voluntary movement, maintenance of posture and equilibrium, regulation of muscle tone, and motor learning. Although it does not initiate movement directly, it modulates motor activity and contributes to the precision and timing of movements.

The cerebellum is highly developed in the dog and plays a major role in coordination of movement and motor control.