Dermatomes

Part of speech: noun

Definitions

1. A type of skin segment that is innervated by specific spinal nerves
2. areas of skin that can be mapped according to corresponding nerve roots
3. distinct segments of skin associated with the sensory distribution of specific spinal nerves

Etymology: "Dermatomes" is the plural of "dermatome," and the singular word is a compound of two Greek elements: "derma," meaning skin, and "-tome," from "tomos," meaning a cutting or a section. The sense of "-tome" that matters here is the one found in "instrument for cutting," the same element that appears in words like "microtome," a tool for slicing thin specimens. The combination is a technical coinage built from classical parts, so the ancient Greeks themselves never used it for a patch of skin. The inflected form is simply what you get when you talk about more than one such region, so the story belongs to the singular. Its meaning as "patch of skin" is also the sense that makes the Greek pieces fit together: a "dermatome" is a defined area of skin supplied by a single spinal nerve root, a territory that can be mapped and cut apart in the imagination of anatomists.