Trousseau sign of latent tetany (not to be confused with Trousseau syndrome) is highly specific for hypocalcemia . It may be elicited by placing a blood pressure cuff over the upper arm and inflating to above systolic pressure for 2-3 minutes. This reduces arterial supply to the forearm. The ischemia, in the context of hypocalcemia, and mediated by the mechanism of hypocalcemic neuronal irritability, leads to muscular spasm of the wrist and hand (carpopedal spasm). The sign is seen in 94% with hypocalcemia and only 1% of those with normal calcium levels (i.e. 94% sensitivity and 99% specificity)
History and etymology
Armand Trousseau (1801-1867), was a French physician who was the first to describe his eponymous sign .