The corticospinal tract originates in several parts of the brain, including not just the motor areas, but also the primary somatosensory cortex and premotor areas.[1] Most of the neurons originate in the primary motor cortex (precentral gyrus, Brodmann area 4) or the premotor frontal areas.[2][3] About 30% of corticospinal neurons originate in the primary motor cortex, 30% more in premotor cortex and supplementary motor areas, with the remaining 40% distributed between the somatosensory cortex, the parietal lobe, and cingulate gyrus.[4] These upper motor neurons originate in layer V pyramidal cells of the neocortex,[1] and travel through the posterior limb of the internal capsule in the forebrain, to enter the cerebral crus at the base of the midbrain. Then both tracts pass through the brain stem, from the pons and then to the medulla.[2] The corticospinal tract, along with the corticobulbar tract, form two pyramids on either side of the medulla of the brainstem—and give their name as pyramidal tracts.[1] Corticospinal neurons synapse directly onto alpha motor neurons for direct muscle control.