A patient has tingling and numbness in his right leg following application of a long leg cast. The patient’s discomfort is most likely the result of:

• A. Reduced venous return
• B. Bone healing
• C. Arterial insufficiency
• D. Nerve compression

Answer: (D)

Pressure from the cast on a nerve explains the tingling and numbness best. When a cast is tight or swells underneath it, it can compress a nerve in the leg, causing paresthesias and sensory loss distal to the cast. Nerves are susceptible to external pressure, and this compression often presents as numbness or burning/tingling rather than just pain.

Other possibilities tend to produce different signs. Reduced venous return would usually cause swelling and a feeling of fullness or aching, not focused numbness. Arterial insufficiency would present with a pale, cool limb, weak or absent pulses, and severe pain, rather than sensory changes. Bone healing itself typically causes localized pain at the fracture site and does not explain new numbness in a distal area.

If numbness or tingling appears, the cast should be checked for tightness or swelling underneath, and neurovascular status should be reassessed promptly to prevent nerve injury.