Spinal cord

The transition of the rhombencephalon into the spinal cord (medulla spinalis) occurs around the area of the cervical flexure. As a result of the massive expansion of the motor columns, the basal plate widens ventrally and forms the ventral horns (ventral columns). The anterior median fissure is situated between these bulges. The spinal cord is thicker in the cervical and lumbosacral areas than elsewhere. Due to innervation of the limbs, there is less cell death in these areas. This is not due to increased growth, as the terms intumescentia cervicalis and lumbosacralis might suggest.