The anterior corticospinal tract is formed at the level of the of the medullary pyramids, where the majority (90%) of descending corticospinal tract fibres decussate to form the lateral corticospinal tract. The remaining non-decussating fibres (10%) form the much smaller anterior corticospinal tract 1,2.
It descends in the anterior funiculus of the spinal cord, lying close to the anterior median fissure. At each relevant level, fibres cross the anterior spinal commissure of the spinal cord to synapse with ventral horn motor neurones. The anterior corticospinal tract thus becomes smaller as it descends, ending at the level of the mid-thoracic cord.
On this page:
Images:
Variant anatomy
In some cases, the anterior corticospinal tract is absent. In rare cases, this tract may contain all corticospinal fibres.
Function
The anterior corticospinal tract is primarily responsible for gross and postural movement of the trunk and proximal musculature 3.
Unable to process the form. Check for errors and try again.
