- Corticospinal (pyramidal) tract: chief descending motor pathway, about 1 million fibres, from upper motor neurons (UMNs) in the cerebral cortex to lower motor neurons (LMNs) in the spinal anterior horn.
Origin
- Arises chiefly from pyramidal cells (of Betz) of the motor area of the cerebral cortex; a smaller contribution arises from other cortical areas.
Course and Decussation
- Descends through corona radiata, internal capsule, crus cerebri, ventral pons and the pyramids of medulla oblongata to the pyramidal decussation.
schematic course of the pyramidal tracts Schematic course of the pyramidal tracts.