Damage to the radial nerve typically results in which functional loss?

Damage to the radial nerve typically results in which functional loss?

• A. Median nerve: loss of forearm and thumb opposition
• B. Ulnar nerve: loss of thumb adduction
• C. Carpal tunnel syndrome
• D. Radial nerve: loss of elbow, wrist, finger and thumb extension

Answer: (D)

The radial nerve is the main motor supplier for the extensor muscles of the arm and forearm, so it controls straightening the elbow, wrist, fingers, and thumb. When it’s damaged, the triceps can’t extend the elbow and the forearm extensors can’t extend the wrist or the digits, including the thumb. This produces a classic inability to straighten the elbow and to extend the wrist and fingers, often seen as a wrist drop. This pattern is distinct from median nerve deficits (which affect thumb opposition) and ulnar nerve deficits (which affect thumb adduction), and from carpal tunnel syndrome (median nerve compression with different sensory/motor signs). So the typical functional loss with radial nerve injury is loss of elbow, wrist, finger, and thumb extension.

The radial nerve is the main motor supplier for the extensor muscles of the arm and forearm, so it controls straightening the elbow, wrist, fingers, and thumb. When it’s damaged, the triceps can’t extend the elbow and the forearm extensors can’t extend the wrist or the digits, including the thumb. This produces a classic inability to straighten the elbow and to extend the wrist and fingers, often seen as a wrist drop. This pattern is distinct from median nerve deficits (which affect thumb opposition) and ulnar nerve deficits (which affect thumb adduction), and from carpal tunnel syndrome (median nerve compression with different sensory/motor signs). So the typical functional loss with radial nerve injury is loss of elbow, wrist, finger, and thumb extension.