Low power of the lumbar spinal cord. The ventral side is to the bottom. White matter is peripheral and the H-shaped gray matter is central (only half the H is seen). Look for the central canal: what is its lining called? (Ans: the ependyma.) Note deep ventral median fissure and identify the dorsal surface. Where would the lower motor neuron perikarya be located? (Ans: in the ventral horn grey matter). Myelin stain.