Upper Limb Nerve Injuries

Question 1

What is the course of the radial nerve?

Answer 1

Nerve arises in the axilla posterior to axillary artery
Gives off branches to triceps brachii
Travels down radial groove of the humerus
Travels anterior to lateral epicondyle through cubital fossa
Divides into deep motor and superficial sensory branches

Question 2

What is the motor function of the radial nerve?

Answer 2

Posterior arm

Posterior forearm

Question 3

What are the sensory functions of the radial nerve?

Answer 3

Lower lateral cutaneous nerve of arm
- lateral arm

Posterior cutaneous nerve of arm
- posterior arm

Posterior cutaneous nerve of forearm
- middle of posterior forearm

Superficial branch

• dorsal lateral 3.5 digits
• dorsum of hand

Question 4

What is the effect of radial nerve injury in the axilla?

Answer 4

Loss of elbow extension
Loss of wrist extension
Loss of finger extension

Loss of snsation

• lateral arm
• posterior arm
• posterior forearm
• dorsal surface of lateral 3.5 digits

Question 5

What is the presentation of a radial nerve injury in the axilla?

Answer 5

Wrist drop

Question 6

What is the effect of radial nerve injury in the radial groove?

Answer 6

Loss of wrist extension
Loss of finger extension

Loss of sensation
- dorsal 3.5 digits

Question 7

What is the presentation of a radial nerve injury in the radial groove?

Answer 7

Wrist drop

Question 8

What is the effect of injury to the superficial branch to the radial nerve?

Answer 8

Sensory loss of dorsal lateral 3.5 digits

Question 9

What is the effect of injury to the deep branch of the radial nerve?

Answer 9

Loss of most muscles in posterior forearm

No wrist drop - extensor carpi radialis unaffected

Question 10

What can cause radial nerve injury in the axilla?

Answer 10

Shoulder dislocation
Proximal humerus fracture
Excessive pressure on axilla

Question 11

What can cause radial nerve injury in the radial groove?

Answer 11

Humeral shaft fracture

Question 12

What can cause injury to the superficial branch of the radial nerve?

Answer 12

Stabbing or laceration of forearm

Question 13

What can cause injury to the deep branch of the radial nerve?

Answer 13

Fracture of radial head

Posterior dislocation of radius

Question 14

What is the course of the median nerve?

Answer 14

Originates in axilla
Travels down arm lateral to brachial artery
Crosses brachial artery to enter anterior forearm via cubital fossa
Travels between FDP + FDS
Gives off anterior interosseous nerve + palmar cutaenous nerve
Enters hand via carpal tunnel
Divides into recurrent branch + palmar digital branch

Question 15

What is the function of the anterior interosseous nerve?

Answer 15

Supplies deep muscles in anterior forearm

Question 16

What is the function of the palmar cutaneous nerve?

Answer 16

Innervates skin of lateral palm

Question 17

What is the function of the recurrent branch of the median nerve?

Answer 17

Innervates thenar muscles

Question 18

What is the function of the palmar digital branch of the median nerve?

Answer 18

Innervates palmar surface of lateral 3.5 digits

Question 19

What are the motor functions of the median nerve?

Answer 19

Innervates flexor + pronator muscles in anterior forearm

Innervates thenar muscles

Innervates the lateral 2 lumbricals

Question 20

What are the sensory functions of the median nerve?

Answer 20

Lateral palm

Palmar lateral 3.5 digits

Question 21

What can cause median nerve injury at the elbow?

Answer 21

Supracondylar fracture of the humerus

Question 22

What is the effect of a median nerve injury at the elbow?

Answer 22

Flexors + pronators paralysed - except flexor carpi ulnaris + medial FDP
Loss of thumb flexion
Loss of lateral 2 lumbricals - unable to flex MCPJs or extend IPJs of index and middle fingers

Loss of sensation

• lateral palm
• palmar lateral 3.5 digits

Question 23

What are the signs of a median nerve injury at the elbow?

Answer 23

Thenar eminence wasted

Constant forearm supination

If tries to make fist - only little + ring fingers can flex

Question 24

What can cause median nerve injury at the wrist?

Answer 24

Laceration proximal to flexor retinaculum

Question 25

What is the effect of median nerve injury at the wrist?

Answer 25

Loss of thumb opposition Loss of flexion of index + middle fingers Loss of sensation - lateral palm - palmar lateral 3.5 digits

Question 26

What is the course of the ulnar nerve?

Answer 26

Originates in axilla Descends down medial aspect of arm Passes posterior to medial epicondyle Pierces the heads of flexor carpi ulnaris and travels deep to muscle Gives off musclar branch + palmar cutaneous branch + dorsal cutaneous branch Travels superficial to flexor retinaculum at wrist Enters hand via Guyon's canal

Question 27

What is the function of the muscular branch of the ulnar nerve?

Answer 27

Innervates flexor carpi ulnaris + FDP

Question 28

What is the function of the palmar cutaneous branch of the ulnar nerve?

Answer 28

Innervates medial half of palm

Question 29

What is the function of the dorsal cutaneous branch of the ulnar nerve?

Answer 29

Innervates dorsal surface of medial 1.5 digits

Question 30

What are the motor functions of the ulnar nerve?

Answer 30

Innervates the intrinsic hand muscles (except thenar + lateral 2 lumbricals) Innervates flexor carpi ulnaris Innervates medial half of FDP

Question 31

What is the sensory function of the ulnar nerve?

Answer 31

Innervates anterior + posterior surfaces of the medial 1.5 fingers

Question 32

What can cause ulnar nerve injury at the elbow?

Answer 32

Trauma t medial epicondyle | Cubital tunnel compression

Question 33

What is the effect of ulnar nerve injury at the elbow?

Answer 33

Flexion of writ can only occur with abduction Loss of finger adduction/abduction Loss of movement of ring/little finger Loss of thumb adduction Loss of sensation - medial 1.5 digits

Question 34

What is the sign of ulnar nerve injury at the elbow?

Answer 34

Positive Froment sign - cannot grip paper between thumb + finger Cannot grip paper between fingers Hypothenar wasting

Question 35

What can cause injury to the ulnar nerve at the wrist?

Answer 35

Laceration to anterior wrist

Question 36

What are the effects of ulnar nerve injury at the wrist?

Answer 36

Loss of abduction + adduction of fingers Loss of movement of ring/little fingers Loss of thumb adduction Loss of sensation - palmar medial 1.5 digits

Question 37

What is the sign of ulnar nerve injury at the wrist?

Answer 37

Positive Froment sign - cannot grip paper between thumb + finger Cannot grip paper between fingers Hypothenar wasting

Question 38

What are the signs of musculocutaneous nerve injury?

Answer 38

Weak shoulder + elbow flexion Loss of sensation over lateral forearm

Question 39

What are signs of axillary nerve injury?

Answer 39

Loss of abduction Loss of sensation over regimental badge area