corticospinal fibers
corticospinal fibres

The middle third of the crus cerebri contains the corticobulbar and corticospinal fibers.

Corticospinal fibers destined for the legs are spared due to their more external location in the spinal cord.

These fibers run alongside the corticospinal fibers.

Most of the corticospinal fibers (about 80%) cross over to the contralateral side in the medulla oblongata (pyramidal decussation).

It is formed by approximately 2% of the corticospinal fibers that do not cross to the opposite side of the brainstem in the pyramidal decussation.

These symptoms indicate a lesion in the medulla involving the corticospinal fibers in the pyramid and the exiting hypoglossal nerve roots).

The two pyramids contain the motor fibers that pass from the brain to the medulla oblongata and medulla spinalis, corticobulbar and corticospinal fibers.

The posterior limb of the internal capsule contains corticospinal fibers, sensory fibers (including the medial lemniscus and the anterolateral system) from the body and a few corticobulbar fibers.

They were particularly impressed by a phase of the study that showed that an animal could still move its paw normally when only 1 percent to 2 percent of its corticospinal fibers remained intact.