Cerebellum

Cerebellum literally means little brain - and it looks like a miniature version of the brain, or cerebrum.

The cerebellum coordinates movements, controls posture, balance and fine motor movement, and is involved in motor learning - like learning how to ride a bicycle.

The cerebellum sits in the posterior part of the skull called the posterior cranial fossa.

Above it are the occipital and temporal lobes of the brain. It’s separated from the brain by a fibrous membrane called the tentorium cerebelli - a fold of dura matter which is one of the layers called meninges that covers the brain and spinal cord.

The cerebellum lies posterior to the brainstem and is attached to it by a stalk of tissue divided into three parts - the superior, middle, and inferior peduncles.

These peduncles contain nerve axons going back and forth between the cerebellum and the brain, the internal ear, and the spinal cord via the brainstem.

The cerebellum consists of two hemispheres separated by a narrow, ridge in the middle called the vermis.

Now if we look at a cross-section, we can see three lobes.

We have the anterior lobe superiorly, and it is separated from the posterior lobe by the primary fissure.

At the tip of the posterior lobe is a very tiny lobe called the flocculonodular lobe and these two are separated by the posterolateral fissure.

The outer layer of the cerebellum is called the cortex and it’s folded into many tiny wrinkles called folia. These are much smaller than the wrinkles found on the cerebrum, and this allows it to have a larger surface area when unfolded even though it occupies only 10% of the brain volume.