Chvostek's Sign is a facial twitch caused by tapping on the facial nerve as it crosses in front of the tragus of the ear, near the Parotid gland. It is indicative of hyperirritability of the nervus facialis, and is symptomatic of Tetany and Hypocalcemia.
The twitch is manifested as contractions of the eye, corner of the mouth, or cheek muscles, coinciding directly with the tapping.
Other names for it include Weiss' Sign, the Chvostek-Weiss Sign, and the Schultze-Chvostek Sign.