Grey matter of the spinal cord

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Structure of the gray matter of the spinal cord in cross section.

Like the rest of the central nervous system, the spinal cord is composed of white and gray matter. The only difference is that the gray matter in the spinal cord is internal to the white matter, whereas the brain has the opposite organization. 

The gray matter of the spinal cord is a butterfly-shaped structure made up of neuronal cell bodies, glial cells and neuropile (unmyelinated axons, dendrites and glial cell processes). 

The gray matter can be functionally divided into three main regions:

• The anterior horn is responsible for motor function;
• The lateral (intermediate) horn is only present in the thoracic region and predominantly responsible for autonomic functions;
• The posterior horn is mainly responsible for sensory functions. 

In addition, on the basis of cytoarchitecture, the gray matter of the spinal cord can also be divided into layers (Rexed laminae). There are ten laminae in total and they are numbered sequentially (I-X) from dorsal to ventral. 

At the center of the spinal cord is a canal filled with cerebrospinal fluid known as the central canal. The gray matter which surrounds the central canal is composed of the anterior and posterior gray commissures that bridge the anterior and posterior horns of each half of the spinal cord.