The cerebellum, sometimes known as the "small brain," is a structure that lies underneath the occipital and temporal lobes of the cerebral cortex in the rear of the brain.
The cerebellum's primary job is to keep the body in proper balance, posture, and tone.
The cerebellum also serves other purposes, such as synchronization and fine-tuning of actions, like when using a bicycle or performing a musical instrument (e.g., guitar). Multiple muscle groups work together to coordinate.