The O'Riain wrinkle test involves which procedure?

The O'Riain wrinkle test involves which procedure?

• A. Active finger flexion test to assess grip strength
• B. Keep the hand submerged and observe lack of wrinkles
• C. Tapping over the nerve to elicit tingling
• D. Electrodiagnostic nerve conduction study

Answer: (B)

The main idea is to test autonomic (vasomotor) function of the hand. When the hand is immersed in warm water, normal sympathetic activity causes the skin to wrinkle. If the nerves supplying the hand are injured and sympathetic innervation is disrupted, the skin may not wrinkle as it should. So keeping the hand submerged and looking for a lack of wrinkles is a quick bedside way to suggest sympathetic denervation from nerve injury. The other actions—testing grip strength by active flexion, tapping to elicit tingling, or performing an electrodiagnostic nerve study—assess motor function, sensory irritability, or formal conduction, not this autonomic wrinkling response.

The main idea is to test autonomic (vasomotor) function of the hand. When the hand is immersed in warm water, normal sympathetic activity causes the skin to wrinkle. If the nerves supplying the hand are injured and sympathetic innervation is disrupted, the skin may not wrinkle as it should. So keeping the hand submerged and looking for a lack of wrinkles is a quick bedside way to suggest sympathetic denervation from nerve injury. The other actions—testing grip strength by active flexion, tapping to elicit tingling, or performing an electrodiagnostic nerve study—assess motor function, sensory irritability, or formal conduction, not this autonomic wrinkling response.