Overview Introduction Function to smoothly coordinate movement to play a role in motor planning and balance Anatomy the cerebellum is derived from the metencephalon and is found dorsally to the pons and rostral medulla which are attached by cerebellar peduncles between the cerebellum and this portion of the brainstem you will find the fourth ventricle the cerebellum contains the vermis and flocculonodular lobes which play an important role in proximal and truncal muscle control (vermis) vestibulo-ocular control (flocculonodular lobes) cerebellar hemisphere can be divided into intermediate hemisphere which plays an important role in distal appendicular muscle control lateral hemisphere which plays an important role in motor planning cerebellar peduncles superior cerebellar peduncles mainly carries output signals middle and inferior cerebellar peduncles mainly carries input signals to the cerebellum deep cerebellar nuclei can be arranged from lateral → medial as Dendate nuclei Eboliform Globos Fastigial mnemonic: "Dont Eat Greasy Food" Circuitry input brain (via the pontocerebellar and climbing fiber) to the cerebellum via the middle cerebellar peduncle spinal cord (via the spinocerebellar and climbing fibers) to the cerebellum via the inferior cerebellar peduncle (there are exceptions) vestibular system to the cerebellum via juxtarestiform body (in the inferior cerebellar peduncle) output all cerebellar outputs are carried by Purkinje cells which synapse in the deep cerebellar nuclei or vestibular nuclei which deep cerebellar nuclei the Purkinje cell synapse with is dependent on where the Purkinje cell arose from Purkinje cells from lateral cerebellum synapse to the dendate nucleus which exits the cerebellum via the superior cerebellar peduncle → contralateral VL of the thalamus → motor cortex and supplementary motor areas to influence the corticospinal system for motor planning intermediate cerebellum synapses to the eboliform and globose nucleus exits the cerebellum via the superior cerebllar pendcuncle → contralateral VL of the thalamus → motor cortex and supplementary motor areas to influence the lateral corticospinal tract vermis synapses to the fastigial nucleus eventually influencing the medial motor system flocculonodular lobe synapses to the vestibular nucleus eventually leading to vestibulo-ocular control Clinical correlate cerebellar disorders typically results in nausea, vomiting, and vertigo slurred speech uncoordinated limb movements dysmetria (under- or over-shooting towards a target) dysrhythmia unsteadiness lesion localization lesions to the vermis results in truncal ataxia lesions to the flocculonodular lobe results in eye movement abnormalities lesions to the cerebellar hemispheres results in ipsilateral ataxia Physical exam physical exam maneuvers to test the cerebellum include finger-to-nose and heel-to-shin test finger tapping rapid alternating movement gait testing truncal ataxia can present with a wide-based and unsteady gait testing for ocular dysmetria and nyastagmus