Upper Limb Nerve Injuries
Brachial plexus injury
| Brachial plexus injury |
Erb's palsy |
Klumpke's palsy |
| Mechanism of injury |
Excessive increase in angle between neck and shoulder e.g. during breech delivery or from fall from motorbike or horse |
Sudden excessive abduction e.g. person catching something overhead as they fall or during a difficult delivery |
| Nerve roots affected |
C5, C6 |
C8, T1 |
| Nerves affected |
Musculocutaneous, axillary, suprascapular and nerve to subclavius |
Ulnar and median nerves |
| Muscles affected |
Supraspinatus, infraspinatus, subclavius, biceps brachii, brachialis, coracobrachialis, deltoid and teres minor |
All small muscles of hand (flexor muscles in forearm innervated by different nerve roots) |
| Motor loss |
Abduction, flexion and lateral rotation of arm, flexion and supination of forearm |
Intrinsic hand movements |
| Sensory loss |
Lateral arm |
Medial arm |
| Deformities |
Waiter's tip |
Claw hand |
Long thoracic nerve injury
The long thoracic nerve is prone to injury due to its excessive length and superficial location on the lateral thoracic wall on the external surface of the serratus anterior muscle, just deep to skin and subcutaneous fascia.
Injury to this nerve may occur due to:
- Trauma or surgery
- A direct blow to the rib area
- Overstretching or strenuous repetitive movements of the arms
- Sustained bearing of excessive weight over the shoulder
Damage to the long thoracic nerve results in weakness/paralysis of the serratus anterior muscle. Loss of function of this muscle causes the medial border, and particularly the inferior angle, of the scapula to elevate away from the thoracic wall, resulting in the characteristic 'winging' of the scapula. This deformity becomes more pronounced if the patient presses the upper limb against a wall. Furthermore, normal elevation of the arm is no longer possible.
Musculocutaneous nerve injury
| Nerve |
Musculocutaneous |
| Mechanism of injury |
Stab wound in axilla |
| Motor loss |
Weakness of flexion and supination of the forearm, weakness of arm flexion |
| Sensory loss |
Lateral aspect of forearm |
Axillary nerve injury
| Nerve |
Axillary |
| Mechanism of injury |
Dislocation of the glenohumeral joint, fracture of the surgical neck of the humerus, trauma or surgery to the shoulder, incorrect use of axillary crutches |
| Motor loss |
Loss of abduction of the arm at the glenohumeral joint and weakness of lateral rotation |
| Sensory loss |
Lateral arm (regimental badge area) |
| Signs |
Atrophy of deltoid - flattened shoulder appearance |
Radial nerve injury
| Lesion |
In axilla |
In spiral groove |
In forearm (superficial branch) |
In forearm (deep branch) |
| Mechanism |
Glenohumeral joint dislocation, fracture of proximal humerus, 'Saturday night syndrome' |
Fracture of midshaft of humerus |
Stabbing/laceration of forearm |
Fracture of radial head or posterior dislocation of radius |
| Motor Loss |
Loss of extension at elbow, wrist and fingers |
Loss of extension at wrist and fingers (triceps brachii spared) |
None |
Weakness of extension at wrist and fingers (extensor carpi radialis spared) |
| Sensory Loss |
Lower lateral arm, posterior arm, posterior forearm, dorsum of lateral hand and three and a half fingers |
Dorsum of lateral hand and three and a half fingers (cutaneous branches of arm and forearm spared) |
Dorsum of lateral hand and three and a half fingers |
None |
| Signs |
Wrist drop (unopposed wrist flexion), weakness of hand grip (finger flexion is weak as the long flexor tendons are not under tension) |
Wrist drop, weak hand grip |
None |
Wrist drop not typically seen (extensor carpi radialis spared) |
Median nerve injury
| Lesion |
Proximal (arm, elbow, proximal forearm) |
Distal (wrist) |
| Mechanisms |
Supracondylar fracture, stab wound to arm or forearm |
Lacerations just proximal to flexor retinaculum |
| Motor Loss |
Forearm pronation, wrist flexion and abduction, index and middle finger flexion, thumb flexion, abduction and opposition |
Thumb flexion at MCPJ, abduction and opposition, flexion of index and middle finger MCPJ |
| Sensory Loss |
Lateral aspect of palm and palmar surface and fingertips of lateral three and a half digits |
Palmar surface and fingertips of lateral three and a half digits |
| Signs |
Forearm rests in supination with wrist in ulnar deviation and thumb extended, thenar eminence wasting, hand of Benediction (when asked to make a fist, the patient will be able to flex the little and ring fingers but not the index and middle fingers) |
Thenar eminence wasting |
Ulnar nerve injury
| Lesion |
Proximal (at elbow) |
Distal (at wrist) |
| Mechanism |
Fracture of medial epicondyle |
Laceration at wrist |
| Motor Loss |
Wrist flexion and adduction, finger abduction and adduction, flexion of ring and little finger, abduction and opposition of little finger, thumb adduction, extension of IPJs of all digits (less so at index and middle finger due to sparing of lateral two lumbricals) |
Finger abduction and adduction, flexion of ring and little finger, abduction and opposition of little finger, thumb adduction, extension at IPJs |
| Sensory Loss |
Medial half of palm, palmar and dorsal surface of medial one and a half fingers and medial dorsum of hand |
Palmar surface of medial one and a half fingers |
| Signs |
Hand held in abduction (due to unopposed action of flexor carpi radialis), Froment's sign (patient is asked to hold a piece of paper between thumb and flat palm as paper is pulled away, patient will flex thumb at IPJ to maintain hold - tests adductor pollicis muscle), hypothenar eminence wasting, N.B. claw hand not typically seen due to paralysis of the flexor digitorum profundus |
Claw hand (unopposed extension at MCPJ and unopposed flexion at IPJs of ring and little finger), hypothenar eminence wasting, Froment's sign |
