Lateral corticospinal tract

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The most important motor pathways of the CNS.

The lateral corticospinal tract is one of the two divisions of the corticospinal pathway and is the largest descending motor pathway in the body. The lateral corticospinal tract is responsible for the voluntary movement of the contralateral upper and lower limbs.

The upper motor neurons, the giant pyramidal cells (of Betz), descend from the primary motor cortex until the medulla oblongata, where 75-90% of them decussate (pyramidal decussation), forming the lateral corticospinal tract. The tract fibers then continue caudally through the lateral funiculus of the spinal cord, synapsing with lower motor neurons in the anterior grey horn on the same side. These lower motor neurons exit the spinal cord through the ventral roots to form peripheral nerves which innervate the skeletal muscles of upper and lower limbs.