dermatoomes

Dermatomes are specific areas of skin that are primarily supplied by a single spinal nerve root. Each spinal nerve, emerging from the vertebral column, is responsible for carrying sensory information from a particular region of the body to the central nervous system. The pattern of these sensory innervations creates distinct dermatomes.

There are 31 pairs of spinal nerves in humans, categorized into cervical, thoracic, lumbar, and sacral regions. The cervical nerves (C1-C8) generally supply the neck, shoulders, and arms. The thoracic nerves (T1-T12) innervate the chest and abdomen. Lumbar nerves (L1-L5) are responsible for the front of the legs and feet, while the sacral nerves (S1-S5) cover the back of the legs, buttocks, and perineum. The C1 nerve root typically has no dermatome.

Understanding dermatomes is crucial in medical diagnosis, particularly for neurologists and physical therapists. By testing for sensation in specific dermatomal areas, clinicians can help pinpoint the level of a spinal cord injury or identify the affected spinal nerve root in conditions like herniated discs or nerve compression. For example, if a patient reports numbness or tingling in a specific pattern on their arm, it can suggest an issue with a particular cervical nerve root. Similarly, pain radiating down a leg in a specific distribution can indicate lumbar or sacral nerve root involvement. This mapping of skin to nerves allows for a more precise localization of neurological problems within the spinal cord and peripheral nervous system.