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Radial nerve palsy



  • The radial nerve is the most frequently injured major nerve in the upper limb1
  • Radial nerve injuries are considered the least debilitating of the upper limb nerve injuries
  • Injuries can be dividied into high, complete radial nerve injury and low, posterior interosseus radial nerve injury (PIN injury)


  • In 11,8-12.3% of patients with radial palsy fracture of the shaft of the humerus is sited as the cause2,3
  • Gunshot injuries
  • Side-effect of surgical interventions
    • Particularly vulnerable around the mid-shaft of the humerus
    • Superficial branches of the nerve can also be damaged during arthroscopy of the shoulder
  • Cutting of the nerve by glass shards or knife
  • Intra-muscular injections
  • Saturday-night palsy and similar compression injuries following prolonged pressure on the nerve, as well as compression by tumors



  • Injury can occur at any part along the pathway of the radial nerve
  • It is particularly vulnerable close to the humeral shaft (in relation to fractures), and around the elbow
  • Most injuries occur distal to the triceps olecranon insertion
  • The nerve passes
    • Across the latissimus dorsi muscle
    • Innervates the triceps muscle between the lateral and medial heads
    • Pierces the intermuscular septum
    • Enters the anterior compartment between brachialis and brachioradialis about 12cm proximal to the lateral epicondyle
    • Passes anterior to lateral condyle of humerus
    • It runs under the brachioradialis
    • In the distal forearm it emerges under the brachioradialis tendon at around 9cm proximal to the styloideus radius
    • It runs between the two head of the supinator muscle in the hand (posterior interosseous nerve)


Risk factors

  • Close proximity to the bone makes it particularly vulnerable when fractures occur



  • Maintaining function is important, maintaining a full passive range of motion in all affected joints
  • Recovery is dependent on the following factors4
    • Age
    • Gender
    • Repair time (surgery)
    • Size of the defect
    • Duration of follow-up
  • When testing during the recovery period, note that the brachioradialis is usually the first muscle to recover, followed by extensor carpi radialis longus and extensor carpi radialis brevis



  • Muscles innervated by the radial nerve can be tested for strength and function
    • Triceps
    • Supinator
    • Wrist and finger extensors



  • If there is no clinical improvement after a period of conservative treatment, surgery is indicated
  • If fractures are the cause of the injury, then early surgical exploration and fracture repair has the best outcome with 89,8% of recovery of function, compared to 77,2% nonsurgically5
    • Patients who did not recover spontaneously and then was treated surgically within 8 weeks of their injury had a recovery rate of 68,1%