What nerve supplies the skin?

The skin is supplied by sensory nerves that transmit information about touch, temperature, and pain to the central nervous system. These sensory nerves are part of the peripheral nervous system and are composed of sensory neurons (afferent neurons). The specific nerves that supply the skin vary depending on the region of the body.

Here are some of the main nerves that supply the skin in different areas:

1. Trigeminal Nerve (Cranial Nerve V): Supplies the skin of the face, scalp, and forehead.

2. Glossopharyngeal Nerve (Cranial Nerve IX): Supplies the skin of the back of the tongue and part of the ear.

3. Vagus Nerve (Cranial Nerve X): Supplies the skin of the external ear and part of the neck.

4. Cervical Nerves (C1-C4): Supply the skin of the back of the head, neck, and part of the shoulder.

5. Brachial Plexus: A network of nerves formed by the cervical and thoracic spinal nerves. It supplies the skin of the upper limbs, including the shoulders, arms, forearms, and hands.

6. Thoracic Nerves (T1-T12): Supply the skin of the chest, abdomen, and back.

7. Lumbar and Sacral Nerves (L1-S5): Supply the skin of the lower limbs, including the buttocks, thighs, legs, and feet.

8. Intercostal Nerves: These are branches of the thoracic spinal nerves and supply the skin between the ribs.

9. Femoral Nerve: Supplies the skin of the anterior thigh and part of the lower leg.

10. Sciatic Nerve: The largest nerve in the body formed by the union of lumbar and sacral nerve roots. It supplies the skin of the back of the thigh, leg, and foot.

The distribution of cutaneous innervation can vary between individuals, and there may be some overlap between the areas supplied by different nerves. Dermatomes are specific areas of skin supplied by a single spinal nerve. Understanding the nerve supply to the skin helps in diagnosing and treating conditions affecting the sensory function of the skin.