.of latent tetany.elicited by tapping facial n.at the angle of the jaw;that causes contration of facial muscled.with twitching of nasolapial folds due to hypocalcemia of various etiologirs.
4-alchilic persons with diarrha
5-pt taking excessive doses duretics& aminoglycosides
6-also seen in measles; tetanus& mycedema
*normal in 10-25% of healthy peoples
it has poor sensetivoty& specificity; therefore it is not a relinle signs of hypocalcemia. so s. orrected calium is mandatory for diagnosis of hypocalce