It lies close to the anterior median fissure, and is present only in the upper part of the spinal cord; gradually diminishing in size as it descends, it ends about the middle of the thoracic region.

It consists of descending fibers that arise from cells in the motor area of the ipsilateral cerebral hemisphere.

The impulse travels from these upper motor neurons (located in the pre-central gyrus of the brain) through the anterior column.

In contrast to the fibers for the lateral corticospinal tract, the fibers for the anterior corticospinal tract do not decussate at the level of the medulla oblongata, although they do cross over in the spinal level they innervate.

[citation needed] This article incorporates text in the public domain from page 759 of the 20th edition of Gray's Anatomy (1918) 2° (Spinomesencephalic tract → Superior colliculus of Midbrain tectum)