The supplementary motor corticospinal tract (SMA CST) connects the superior frontal gyrus with the spinal cord. The superior end of this pathway is in the superior frontal gyrus and sweeps anteriorly, anterior to the precentral CST, close to the frontal aslant tract, medial to the superior putaminal projections, and together with subthalamic projections. Inferiorly, SMA CST funnels into the posterior limb of the internal capsule, anterior to the precentral CST, and lateral to the thalamic nuclei. Inferior to the thalamus, SMA CST is anterior to the precentral CST, and then medial to it at the level of the cerebral peduncles, descending into the spinal cord.