Cerebellar vermis

Vermis cerebelli

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What it is
The narrow, worm-like midline strip joining the two cerebellar hemispheres, raised on top (culmen) under the tentorium and sunk below between the hemispheres (vallecula).
Function
Controls posture, balance, gait and eye movements via the fastigial and vestibular nuclei.
Size
About 1-2 cm wide and 5 cm long around its curve
Clinical note
Chronic alcohol damage typically hits the anterior superior vermis, causing a wide-based, staggering gait while arm coordination is relatively spared.

Nearby nervous structures Cerebellar hemisphere, Cerebellar white matter (arbor vitae), Cerebral aqueduct, Facial nerve root (CN VII), Fourth ventricle, Pons, Tentorium cerebelli, Trigeminal nerve root (CN V), Trochlear nerve root (CN IV), Vestibulocochlear nerve root (CN VIII)