Radial nerve palsy in the arm is most commonly caused by a fracture of the humerus and may occur acutely at the time of the injury, secondary to fracture manipulation or from a healing callus.
Radial nerve palsy is characterised by palsy or paralysis of all extensors of the wrist and digits, as well as the forearm supinators. Very proximal lesions also may affect the triceps. Numbness occurs on the dorsoradial aspect of the hand and the dorsal aspect of the radial 3½ digits.
Initially, a period of medical management is required for 6-12 weeks to allow swelling and the palsy to subside. If a palsy develops after a closed manipulation, a further gentle manipulation is carried out.
Open exploration is indicated if there is no relief of the palsy, or if it is felt that the nerve may be entrapped between the fracture fragments. In an open fracture of the humerus with an associated palsy, exploration of the nerve at the time of debridement, as well as possible fixation, is the treatment of choice.
The x-ray shows a fracture of the humerus.