What physiological sign may suggest hypocalcemia when a blood pressure cuff is applied?

The physiological sign that may suggest hypocalcemia when a blood pressure cuff is applied is carpopedal spasm. This sign is indicative of increased neuromuscular excitability, a common characteristic seen in hypocalcemia. When calcium levels in the blood are low, it can lead to increased irritability of nerves and muscles, causing muscle contractions or spasms.

Applying a blood pressure cuff can also contribute to temporary ischemia, which may provoke a spasm in the hands and feet, reflecting carpopedal spasm. This specific spasm typically presents as involuntary contractions in the fingers or toes, which can be visually identified when the cuff is inflated.

The other choices, while they can indicate various medical conditions, do not specifically relate to or suggest hypocalcemia in the context of applying a blood pressure cuff. Cheek puffing is not typically associated with calcium levels, cervical rigidity often suggests meningeal irritation, and severe headaches can be caused by numerous factors unrelated to calcium balance. Thus, carpopedal spasm is the most appropriate physiological sign to identify hypocalcemia in this scenario.