Brain anatomy: Cerebellum

Cerebellum The cerebellum is located behind the dorsal aspect of the pons and the medulla. It is separated from the occipital lobe by the tentorium and fills most of the posterior fossa. A midline portion, the vermis, separates two lateral lobes, or cerebellar hemispheres. The cerebellum consists of the cerebellar cortex and the underlying cerebellar white matter Four paired deep cerebellar nuclei are located within the white matter of the cerebellum Because of the location of the fourth ventricle, ventral to the cerebellum, mass lesions or swelling of the cerebellum can cause obstructive hydrocephalus.

Cerebellar functions The cerebellum has several main functions: coordinating skilled voluntary movements by influencing muscle activity, controlling equilibrium and muscle tone through connections with the vestibular system and the spinal cord and its gamma motor neurons. There is a somatotopic organization of body parts within the cerebellar cortex. In addition, the cerebellum receives collateral input from the sensory and special sensory systems. As might be predicted from the cerebellar homunculi, the vermis tends to control coordination and muscle tone of the trunk, whereas each cerebellar hemisphere controls motor coordination and muscle tone on the same side of the body.

Shows linkage of cortex to cerebellum- extensive pathways in and out

Functions Co-ordination of movement The cortex initiates it and the cerebellum co-ordinates it.

MRI at the level of the 4th ventricle

Damage to the cerebellum Causes a lack of co-ordination: Speaking Walking Tremour

Cerebellar Stroke Dizziness, vomiting Unsteady so that walking is impossible Power, tone and reflexes normal Area of blood in the cerebellum would show on a CT scan