Upper Limb Nerve Injuries Flashcards
What is the course of the radial nerve?
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
What is the motor function of the radial nerve?
Posterior arm
Posterior forearm
What are the sensory functions of the radial nerve?
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
What is the effect of radial nerve injury in the axilla?
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
What is the presentation of a radial nerve injury in the axilla?
Wrist drop
What is the effect of radial nerve injury in the radial groove?
Loss of wrist extension
Loss of finger extension
Loss of sensation
- dorsal 3.5 digits
What is the presentation of a radial nerve injury in the radial groove?
Wrist drop
What is the effect of injury to the superficial branch to the radial nerve?
Sensory loss of dorsal lateral 3.5 digits
What is the effect of injury to the deep branch of the radial nerve?
Loss of most muscles in posterior forearm
No wrist drop - extensor carpi radialis unaffected
What can cause radial nerve injury in the axilla?
Shoulder dislocation
Proximal humerus fracture
Excessive pressure on axilla
What can cause radial nerve injury in the radial groove?
Humeral shaft fracture
What can cause injury to the superficial branch of the radial nerve?
Stabbing or laceration of forearm
What can cause injury to the deep branch of the radial nerve?
Fracture of radial head
Posterior dislocation of radius
What is the course of the median nerve?
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
What is the function of the anterior interosseous nerve?
Supplies deep muscles in anterior forearm
What is the function of the palmar cutaneous nerve?
Innervates skin of lateral palm
What is the function of the recurrent branch of the median nerve?
Innervates thenar muscles
What is the function of the palmar digital branch of the median nerve?
Innervates palmar surface of lateral 3.5 digits
What are the motor functions of the median nerve?
Innervates flexor + pronator muscles in anterior forearm
Innervates thenar muscles
Innervates the lateral 2 lumbricals
What are the sensory functions of the median nerve?
Lateral palm
Palmar lateral 3.5 digits
What can cause median nerve injury at the elbow?
Supracondylar fracture of the humerus
What is the effect of a median nerve injury at the elbow?
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
What are the signs of a median nerve injury at the elbow?
Thenar eminence wasted
Constant forearm supination
If tries to make fist - only little + ring fingers can flex
What can cause median nerve injury at the wrist?
Laceration proximal to flexor retinaculum
What is the effect of median nerve injury at the wrist?
Loss of thumb opposition
Loss of flexion of index + middle fingers
Loss of sensation
- lateral palm
- palmar lateral 3.5 digits
What is the course of the ulnar nerve?
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
What is the function of the muscular branch of the ulnar nerve?
Innervates flexor carpi ulnaris + FDP
What is the function of the palmar cutaneous branch of the ulnar nerve?
Innervates medial half of palm
What is the function of the dorsal cutaneous branch of the ulnar nerve?
Innervates dorsal surface of medial 1.5 digits
What are the motor functions of the ulnar nerve?
Innervates the intrinsic hand muscles (except thenar + lateral 2 lumbricals)
Innervates flexor carpi ulnaris
Innervates medial half of FDP
What is the sensory function of the ulnar nerve?
Innervates anterior + posterior surfaces of the medial 1.5 fingers
What can cause ulnar nerve injury at the elbow?
Trauma t medial epicondyle
Cubital tunnel compression
What is the effect of ulnar nerve injury at the elbow?
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
What is the sign of ulnar nerve injury at the elbow?
Positive Froment sign - cannot grip paper between thumb + finger
Cannot grip paper between fingers
Hypothenar wasting
What can cause injury to the ulnar nerve at the wrist?
Laceration to anterior wrist
What are the effects of ulnar nerve injury at the wrist?
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
What is the sign of ulnar nerve injury at the wrist?
Positive Froment sign - cannot grip paper between thumb + finger
Cannot grip paper between fingers
Hypothenar wasting
What are the signs of musculocutaneous nerve injury?
Weak shoulder + elbow flexion
Loss of sensation over lateral forearm
What are signs of axillary nerve injury?
Loss of abduction
Loss of sensation over regimental badge area
