- any of four tracts of descending motor fibers that extend in pairs down each side of the spinal column and function in voluntary movement.
Origin of pyramidal tract
First recorded in 1885–90
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- A massive bundle of fibers that originates from the motor cortex and the postcentral gyrus and emerges on the ventral surface of the medulla oblongata. Most of the fibers cross to the opposite side in the pyramidal decussation and descend the length of the spinal cord to innervate muscles of the extremities.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.