CMD 377 Lecture Notes - Lecture 17: Supplementary Motor Area, Postcentral Gyrus, Premotor Cortex
Document Summary
Input to the corticospinal tract comes from: primary motor cortex, somatosensory cortex of the postcentral gyrus, premotor cortex, supplementary motor area. Direct projection from the pyramidal cells in the motor areas in the cortex to the sc: lateral corticospinal tract. 85% of fibers that decussate in the caudal medulla. Motor area posterior limb of internal capsule fibers decussate in caudal medulla (pyramidal decussation) terminate in ventral horn of sc or in the brainstem reticular formation: anterior corticospinal tract. Remaining 15-20% of corticospinal fibers that do not decussate. Descend to the sc and termiante on motor or interneurons of ventral horn. Direct projection from the pyramidal cells in the motor areas of the cortex to the brainstem motor nuclei (v, vii, ix, x, xi, xii motor nuclei) Motor areas posterior limb of the internal capsule synapse on motor nuclei in pons, medulla, and sc. Bilateral innervation (exception facial nucleus for lower face)
