The cerebellum lies in the Posterior Fossa posterior to the brainstem. It is seperated from the occipital lobe by the tentorium cerebelli.
It contains of two lateral hemispheres and the midline called the vermis.
An important structure on the inferior surface of the cerebellum called the cerebellar tonsils. The cerebellar tonsils herniate through the foramen magnum causing brainstem compression acutely, or in patients with Arnold-Chiari malformations.
There are three further subdivisions of the cerebellum
An anterior lobe: receives afferent fibres from the spinocerebellar tracts. They are important for the functioning of gait
A Posterior Lobe: importance in regulation of motor tone
Flocculonodular lobe- receives input from the vestibular system
The two tracts responsible are the dorsal spinocerebellar tract relay input from Clarkes column (T1-L4) and ventral spinocerebellar tract (L1-L5). Both of these fibre tracts remain ipsilateral hence cerebellar signs are ipsilateral to the lesion not contra-lateral.
The blood supply includes: Superior Cerebellar, Anterior Inferior and Posterior Inferior cerebellar artery.
Note midline lesions to the flocculus or vermis will produce symptoms affecting the midline eg truncal ataxia and a broad base gait
Hemispheric Lesions always produce lesions that are ispilateral. The pneumonic DANISH P
Dysmetria and Dysdiadokinesia– past-pointing/rebound affect
Ataxia– broad base gait, or loss of balance towards the side of the lesion
Slurred Speech– scanning dysarthria
Hypotonia and Hyporeflexia (typical pendular reflexes)
Causes of Cerebellar Dysfunction
Answering exam questions is not blurting verbal diorrhea it is being concise almost like constipation. This was advice from one of my consultant mentors!
Use surgical or anatomical sieves, it can really help you!
Infectious- cerebellar abscess, viral cerebellitis
Neoplastic- GBM, Metastasis, Medulloblastoma, Haemangioblastoma
Vascular: haemorrhage, infarct
Trauma- traumatic posterior haemorrhage, or tonsillar herniation
Drugs: Alcohol, Anti-epileptics
Metabolic: vitamin B1 deficiency, hypoxia, hypoglyaemia
Degenerative/congenital: Arnold-chiari malformation