Sydenham chorea (St. Vitus dance) - commonest chorea. occurs mainly in girls as a sequela to rheumatic fever. Chorea major (Huntington's disease) -inherited disorder manifests as choreiform movements and progressive dementia. Chorea gravidarum occurs during the 2nd trimester of pregnancy. Ballism and hemiballism -violent flinging movement of one or both extremities due to infarct of the subthalamic nucleus.