APA Dictionary of Psychology

a major motor pathway that originates in the cerebral cortex (see motor cortex), passes through the pyramid of the medulla oblongata, and descends to terminate in the spinal cord. At the pyramid, most of its fibers cross over to form the lateral corticospinal tract; the remaining fibers, forming the smaller anterior corticospinal tract, descend anteriorly in the white matter of the spinal cord to terminate in the anterior horns. See also pyramidal tract.