An indication of tetany in which a unilateral spasm of the oris muscle is initiated by a slight tap over the facial nerve anterior to the external auditory canal.
This sign usually suggests hypocalcemia but can occur normally in about 25% of patients. Typically, it precedes other signs of hypocalcemia and persists
Chvostek’s Sign and Trousseau’s Sign due to Postoperative Acquired Hypoparathyroidism YouTube