Spinal Cord: Cross-sectional Anatomy

In the transverse section of the spinal cord, the gray matter is surrounded by the white matter. The dorsal median sulcus and the ventral median fissure divide the spinal cord into two symmetrical halves.

The middle part of the gray matter, known as the gray commissure, surrounds the CSF-filled central canal. It connects gray matter projections, or horns, on the left and right halves.

The dorsal horns consist of multipolar interneurons, which, together with the axons of sensory neurons, form clusters called dorsal rootlets and dorsal roots.

The ventral horns consist of multipolar somatic motor neurons and interneurons. Their axons form ventral rootlets and ventral roots.

These dorsal and ventral roots fuse laterally, forming the spinal nerves.

The proportion of gray matter varies along the length of the spinal cord.

In the thoracic and upper lumbar regions, the gray matter has additional projections called lateral horns, containing autonomic motor neurons.

The white matter is organized into dorsal, ventral, and lateral regions known as the funiculi.

Each funiculus contains nerve fiber tracts that have sensory or motor functions.