medical definition dystonia
dystonia. Definitions: 1. A syndrome of abnormal muscle contraction that produces repetitive involuntary twisting movements and abnormal posturing of the neck, trunk, face, and extremities. The definition information for dystonia is provided by Stedman's. You can search our medical dictionary here.efinitions: 1. A syndrome of abnormal muscle contraction that produces repetitive involuntary twisting movements and abnormal posturing of the neck, trunk, face, and extremities. The definition information for dystonia is provided by Stedman's.