Also found in: Encyclopedia.
A type of involuntary movement affecting the proximal limb musculature, manifested in jerking, flinging movements of the extremity; caused by a lesion of or near the contralateral subthalamic nucleus. Usually only one side of the body is involved, resulting in hemiballismus.
[G. ballismos, a jumping about]
ballismAn extreme form of CHOREA in which the limbs are flung about violently. It is a disorder of the EXTRAPYRAMIDAL SYSTEM of the brain. STEREOTACTIC SURGERY may be helpful.
violent flinging movements of the limbs, sometimes affecting only one side of the body (hemiballismus).