With reference to shingles a dermatome chart shows which spinal nerve the shingles virus affects, according to MedlinePlus. A dermatome is the band-like distribution of the sensory portion of a nerve along the skin, states Spine-health. Shingles typically affects a single dermatome, reports ShinglesInfo.com.
The chickenpox virus remains dormant in the body after initial exposure, says the CDC. Shingles occurs when the virus reactivates within a particular nerve, usually after many years, according to Penn Medicine. A typical manifestation includes a rash on one side of the body with blisters, itching and pain lasting two to three weeks. The rash restricts itself to one dermatome, and the location of that dermatome indicates which nerve the virus affects.