Chvosteks Sign
Chvostek’s Sign
Chvostek’s sign is contraction of facial muscles provoked by lightly tapping over the facial nerve as it crosses the zygomatic arch. Chvostek’s sign is observed in hypocalcemic states, such as hypoparathyroidism and the respiratory alkalosis associated with hyperventilation. There may be concurrent posturing of the hand, known as main d’accoucheur for its resemblance to the posture adopted for manual delivery of a baby. The pathophysiology of this mechanosensitivity of nerve fibers is uncertain, but is probably related to increased discharges in central pathways. Although hypocalcemia might be expected to impair neuromuscular junction transmission and excitation-contraction coupling (since Ca2+ ions are required for these processes) this does not in fact occur.
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