What Should You Know about Dermatomes?
What is a Dermatome?
A dermatome is the area of the skin of the human anatomy that is mainly supplied by branches of a single spinal sensory nerve root. These spinal sensory nerves enter the nerve root at the spinal cord, and their branches reach to the periphery of the body. The sensory nerves in the periphery of the body are a type of nerve that transmits signals from sensations (for example, pain symptoms, touch, temperature) to the spinal cord from specific areas of our anatomy.
Why Are Dermatomes Important?
To understand dermatomes, it is important to understand the anatomy of the spine. The spinal column is divided into 31 segments, each with a pair (right and left) of anterior and posterior nerve roots. The types of nerves in the anterior and posterior roots are different. Anterior nerve roots are responsible for motor signals to the body, and posterior nerve roots receive sensory signals like pain or other sensory symptoms. The anterior and posterior nerve roots combine on each side to form the spinal nerves as they exit the vertebral canal (the bones of the spine, or backbone).
Where Are Dermatomes Located in the Spinal Column?
The 31 spinal column has 31 spinal nerves, which are composed of 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal spinal nerves. There are specific dermatomes for each of these spinal nerves, except the first cervical spinal nerve. Dermatomes are used to represent the patterns of sensory nerves that cover various parts of the body, include, head and neck, upper extremities (arms, hands, torso etc.), and lower extremities (hip, leg, foot, buttocks, feet, etc.)