Contents
Definition
- 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)
Causes
- 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
Localization
- 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
Development
- 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
Examination
- Muscles innervated by the radial nerve can be tested for strength and function
- Triceps
- Supinator
- Wrist and finger extensors
Treatment
- 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%