The spinal cord

Histology image of the spinal cord. Image copyright: University of Oslo, CC BY-NC-ND 4.0. (Tissue stain: H+E).

This is a cross-section through the lumbar part of the spinal cord, with membranes, nerve roots and spinal nerves. Notice the gray matter is located at the center of the spinal cord as opposed to the cerebral cortex where it is found covering the outside. The gray matter forms a distinct butterfly shape surrounded by white matter in this cross section.