Now, each spinal nerve is in charge of the sensation of a specific area of the skin, called a dermatome.

每一根经都负责着特定区域感觉，该区域称为皮节。

Herpes zoster or shingles is caused by the reactivation of the virus, with vesicles located along one dermatome.

带状疱疹是由病激活导致，皮损沿皮节带状排列。

Dermatomes of the spinal nerves of the sacral plexus cover almost the entire surface of the thigh, leg, and foot.

骶经丛经皮节包括几乎整个大腿、小腿和足表面。

It usually takes 4 weeks for the rash to disappear, but there can be pain in the affected dermatome which lasts for more than 90 days, called postherpetic neuralgia.

皮损一般需要4周消退，但是被感染皮节区疼痛持续可以超过90天，被叫做带状疱疹后经痛。

Below the knee, the pain usually follows the dermatome distribution, for example, if the L4 nerve root is compressed, the pain would radiate along side the medial side of the leg.

在膝盖以下，疼痛通常遵循皮节分布：像是如果L4经根受压，疼痛会沿着小腿内侧放射。