extrapyramidal

adj.
Relating to or involving neural pathways situated outside or independent of the pyramidal tracts.

(ĕk'strə-pĭ-răm'ĭ-dl)
adj.

Relating to or involving neural pathways situated outside or independent of the pyramidal tracts.

Outside the pyramidal tracts.

• e. disease, e. syndrome — any of a group of clinical disorders marked by abnormal involuntary movements, alterations in muscle tone, and postural disturbances.
• e. motor system — see extrapyramidal system (below).
• e. system — a functional, rather than anatomical, unit comprising the nuclei and fibers (excluding those of the pyramidal tract) involved in motor activities; they control and coordinate especially the postural, static, supporting and locomotor mechanisms. It includes the corpus striatum, subthalamic nucleus, substantia nigra and red nucleus, along with their interconnections with the reticular formation, cerebellum and cerebrum; some authorities include the cerebellum and vestibular nuclei. Called also extrapyramidal motor system.