Jactitation (medicine)

Jactitation is an archaic medical term (derived, perhaps as a corruption, from "jactation", meaning a restless tossing and turning of the body, and derived itself from Latin jactare or jacere, both meaning "to throw or hurl") referring to the involuntary spasm of a limb, muscle, or muscle group. This is sometimes seen in fever patients or other situations of physical distress, but may occur in healthy individuals in a hypnogogic state. This hypnagogic jactitation often occurs in the legs, and may occasion a short explanatory dream about stumbling or missing the bottom stair.