The Upper Limb Flashcards
Where is the radial nerve susceptible to injury?
- In the axilla
- In the radial groove
What might you seen if a patient has a radial nerve palsy?
Wrist drop due to unopposed flexion of the wrist as the extensor muscles are innervated by the radial nerve
How would a radial nerve injury occur in the axilla and what clinical picture would you see?
Could happen with dislocation of the shoulder of a proximal humeral fracture, or from excessive pressure
- Wrist drop
- Loss of sensation over all parts of the arm that the radial nerve supplies - lateral and posterior upper arm, posterior forearm and dorsal surface of lateral three digits of the hand
How would a radial nerve injury occur in the axilla and what clinical picture would you see?
Could happen with dislocation of the shoulder of a proximal humeral fracture, or from excessive pressure
- Wrist drop
- Loss of sensation over all parts of the arm that the radial nerve supplies - lateral and posterior upper arm, posterior forearm and dorsal surface of lateral three digits of the hand
How might damage to the radial nerve occur in the radial groove and what clinical picture would you see?
- Fracture of the shaft of the humerus
- Wrist drop
- Loss of sensation to the dorsal surface of the lateral three digits
How could the deep branch of the radial nerve be damaged and what would the clinical picture be?
- Fracture of the radial head or posterior dislocation of the radius at the elbow joint
- No wrist drop but loss of innervation to the posterior compartment of the forearm except supinator and extensor carpi radialis longus
How could the deep branch of the radial nerve be damaged and what would the clinical picture be?
- Fracture of the radial head or posterior dislocation of the radius at the elbow joint
- No wrist drop but loss of innervation to the posterior compartment of the forearm except supinator and extensor carpi radialis longus
- No sensory loss as it is a motor nerve
What could affect the superficial branch of the radial nerve and what would the clinical picture be?
- Laceration the forearm
- No loss of motor function as it is a sensory nerve
- Sensory loss to the dorsal surface of the lateral three digits
What is the sensory function of the axillary nerve?
The regimental badge area/lower deltoid
What is the motor function of the axillary nerve?
- Teres minor
- Deltoid
- Shoulder abductors
From which cord of the brachial plexus does the axillary nerve come from?
Posterior
What are the spinal roots of the axillary nerve?
C5 and C6
How might an injury to the axillary nerve occur and what would you see clinically?
- Trauma to the shoulder
- Paralysis of teres minor and deltoid, therefore unable to abduct the limb
- Loss of sensation over the regimental badge area
What motor function does the musculocutaneous nerve have?
-BBC
Biceps brachii, brachialis and coracobrachialis
What is the sensory function of the musculocutaneous nerve?
Innervation of the lateral surface of the forearm
How might you sustain an injury to the musculocutaneous nerve and what might be seen clinically?
- Stabbing the in the axilla as the nerve is very well protected
- Weakened flexion of the shoulder and the elbow and weakened supination
- Loss of sensation over the lateral side of the forearm
What is the motor function of the median nerve?
Flexor muscles of the anterior compartment of the forearm, thenar muscles and the lateral two lumbricals of the hand
What is the sensory function of the median nerve?
Lateral three and a half digits on the palmar surface of the hand
Which nerve is compressed in carpal tunnel syndrome
Median nerve
What can happen if carpal tunnel syndrome is untreated?
Atrophy and weakness of the thenar muscles
What two tests can you perform to test for carpal tunnel syndrome
- Tinels sign - Tapping the nerve in the carpal tunnel to elicit pain
- Phalens manoever - Holding the wrist in flexion for 60secs to elicit pain/numbness of the median nerve distribution
What might you see if the median nerve is damaged at the elbow and how might this have occurred?
-Supracondylar fracture of the humerus
-Paralysed flexors and pronators therefore the forearm is always supinated and flexion is weak. No flexion of the thumb
Characteristic sign is the Hand of Benediction
-Loss of sensation over the areas that the median nerve innervates
What might you see if the median nerve is damaged at the wrist and how might this occur?
-Lacerations proximal to the flexor retinaculum
-Paralysis of the thenar muscles and the lumbricals that the median nerve innervates
-Loss of sensation in the areas of the hand that the median nerve innervates
Hand of Benediction
What might you see if the median nerve is damaged at the wrist and how might this occur?
-Lacerations proximal to the flexor retinaculum
-Paralysis of the thenar muscles and the lumbricals that the median nerve innervates
-Loss of sensation in the areas of the hand that the median nerve innervates
Hand of Benediction
What is the motor function of the ulnar nerve?
- Muscles of the hand (except thenar muscles and the lateral two lumbricals)
- Flexor carpi ulnaris
- Medial half of flexor digitorum profundus
What is the sensory function of the ulnar nerve?
Anterior and posterior surface of the medial one and a half fingers
How might the ulnar nerve become damaged at the elbow and what would the clinical picture be?
- Fracture of the medial epicondyle
- Patient can’t grip paper placed between fingers as there is loss of motor function of the interossi. There is loss of motor function of flexor carpi ulnaris medial half of the flexor digitorum profundus
How might the ulnar nerve become damaged at the wrist and what would the clinical picture be?
- Laceration to the wrist
- The interossi muscles are paralysed and there is reduction in movement of the medial two fingers due to loss of innervation of the medial lumbricals
- Sensory loss over the palmar side of the medial one and a half fingers
- Gives characteristic ulnar claw
What are the articulating surfaces of the elbow?
- Trochlear notch of the ulnar and the trochlea of the humerus
- Head of the radius and the capitulum of the humerus
What type of joint is the elbow?
Synovial hinge
What movements can the elbow produce and what muscles do this?
- Flexion = Brachialis, Biceps brachii, brachioradialis
- Extension = Anconeus, triceps brachii