[TA] those fibers that cross to the opposite side in the corticospinal (pyramidal) decussation and descend in the posterior half of the lateral funiculus of the spinal cord; they are distributed throughout the length of the spinal cord to interneurons of the zona intermedia of the spinal gray matter, to some of the nuclei of the posterior horn, and to interneuron pools of the anterior horn.corticospinal tract. SYN: tractus corticospinalis lateralis [TA], crossed pyramidal tract, fasciculus corticospinalis lateralis, fasciculus pyramidalis lateralis, lateral pyramidal fasciculus, lateral pyramidal tract, tractus pyramidalis lateralis.