Lateral corticospinal tract

At a glance

Source of the outline

A region of the PAM50 white-matter atlas, drawn at each segment levelLévy et al. 2015; De Leener et al. 2018

Levels with this region in the atlas sections

C1 to S1 (26 levels)

Pathway

Lateral corticospinal tract: voluntary movement of the limbs

What the sources say

“It then passes between the caudate nucleus and putamen of the basal nuclei as a bundle called the internal capsule.” Betts et al. 2022, §14.3

“The tract then passes through the midbrain as the cerebral peduncles, after which it burrows through the pons.” Betts et al. 2022, §14.3

“The defining landmark of the medullary-spinal border is the pyramidal decussation, which is where most of the fibers in the corticospinal tract cross over to the opposite side of the brain.” Betts et al. 2022, §14.3

“The lateral corticospinal tract is composed of the fibers that cross the midline at the pyramidal decussation (see Figure 14.28).” Betts et al. 2022, §14.3

Read more

• Corticospinal tract

  The main route for voluntary movement, from the motor cortex down through the brainstem, across the midline and down the cord to the lower motor neurons. Why a cut on one side of the cord weakens the same side below it.

• Descending motor tracts

  The tracts that carry movement commands down the cord. The corticospinal tract for voluntary movement, and the extrapyramidal tracts from the brainstem for posture, balance, tone and corrections.

• Incomplete cord syndromes

  Why damage to one part of the cord's cross-section gives a recognisable pattern. Brown-Séquard, central cord, anterior cord and posterior cord patterns, explained from the tracts and the blood supply.

• Primary motor cortex

  The strip of cortex in the precentral gyrus that starts voluntary movement. Its upper motor neurons send the corticospinal tract down to the cord, and its activity is what most brain–computer interfaces read.