Nerve injuries to upper limb

Question 1

Injury to radial nerve in spiral groove

Answer 1

Radial nerve runs in spiral groove on posterior surface of shaft of humerus so injured in mid shaft humeral fracture.

Question 2

Will patient still be able to extend elbow in injury to radial nerve in spinal groove?

Answer 2

Yes - nerve supply to long and lateral head of biceps before radial nerve enters spiral groove and medial head of triceps given off in spiral groove but normally proximal to fracture

Question 3

Position of patients wrist and fingers when wrist pronated in injury to radial nerve in spinal groove?

Answer 3

Wrist drop = wrist and fingers flexed due to paralysis of brachioradialis and all extensor muscles.
So unopposed flexor muscles and gravity = wrist drop.

Question 4

Sensory impairment in injury to radial nerve in spinal groove?

Answer 4

• Posterior cutaneous nerve of arms above spinal groove so unaffected
• Lower lateral cutaneous nerve of arm and posterior cutaneous nerve of forearm are high in spiral groove so unaffected
• Paraesthesia - superficial branch of radial nerve distribution

Question 5

High median nerve injury

Answer 5

Above elbow level.
eg. Supracondylar fracture of humerus
Paralyses median muscles of arm and those of forearm and hand.

Question 6

Median muscles of arm, hand and wrist

Answer 6

• Flexor carpi radialis
• Pronator teres
• Palmaris longus
• Flexor digitorum superficialis
• Pronators and flexors of wrist

Question 7

Position of forearm in high median nerve damage

Answer 7

Supinated, adducted wrist

Question 8

Position of hand in high median nerve damage

Answer 8

Hand of Benediction - ring and little finger able to flex, other fingers can’t - hunger games gesture

Question 9

Aped Hand deformity

Answer 9

Prolonged median nerve lesion = thenar wasting, can’t move thumb from hand

Question 10

Sensory loss in high median nerve injury

Answer 10

Sensory loss in whole of region supplied by median nerve

Question 11

Low median nerve injury

Answer 11

At wrist level due to penetrating injury or compression in carpal tunnel.
Ape hand deformity can be seen.

Question 12

Muscles paralysed in low median nerve injury

Answer 12

LOAF

1. Lumbricals to index and middle fingers
2. Opponens pollici
3. Abductor pollicis brevis
4. Flexor pollicis brevis

Question 13

Muscles damaged in ulnar nerve injury at wrist

Answer 13

Adductor pollicis, deep head of flexor pollicis braves, interossei, lumbricals to ring and little finger, palmaris braves and palmar digital branches to ulnar 1 1/2 digits

Question 14

Claw hand in ulnar nerve injury

Answer 14

Little and ring fingers hyperextended at MCPJ and flexed and IP joints

Question 15

High ulnar nerve lesion

Answer 15

At elbow level. Due to medial epicondylar fracture or compression in cubital tunnel.

Question 16

Ulnar paradox

Answer 16

Clawing in high ulnar nerve lesion < than low ulnar nerve lesion.
Would expect proximal injury to be a more pronounced deformity but instead distal injury causes the more pronounced deformity.