"In the precentral gyrus, large neurones known as Betz cells send efferent axons that terminate on the contralateral motor cranial and spinal nuclei. The functional organisation of the precentral gyrus is such that clusters of Betz cells are somatotopically represented by an inverted homunculus. Therefore, head and face regions are innervated by the inferior portion of the precentral gyrus. Conversely, the lower limbs are innervated by the superior portion 4."