ballismus

Full Definition

Ballismus presents as sudden, large-amplitude, involuntary movements that appear as if the patient is throwing or flinging their limbs. It typically results from lesions in the subthalamic nucleus or related basal ganglia structures. Hemiballismus affects one side of the body, while bilateral involvement is called biballismus. The movements are among the most dramatic in neurology.

Usage

Usage note: Distinguish from other hyperkinetic disorders by the violent, flinging quality of movements.

In Context

• "The sudden onset of hemiballismus suggested an acute subthalamic nucleus lesion." — Emergency department report
• "Ballismus movements were so severe that the patient required restraints for safety." — Nursing assessment