MSK Clinical Hand Wrist Elbow Flashcards
What can enlarged axillary lymph nodes be a sign of?
- Lymphedema e.g. caused by infection lymphangitis. Metastases of breast cancer.
How many axillary lymph nodes are there?
5
Pectoral Sub scapular Humeral Central Apical
How can lymph node removal analysis be used clinically? What are two drawbacks of this kind of analysis?
Useful for staging breast cancer
Removal of lymph nodes can lead to lymph oedema (can lead to painful swelling of upper limb)
Risk of damage to long thoracic nerve in this procedure
What can a mid humeral shaft cause injury to?
Radial nerve as runs in the radial groove - Appears as wrist drop
Profunda brachii artery damage
Why does radial nerve injury at the mid-shaft of the humerus result in wrist drop? Why might there be no sensory damage of arm and forearm but sensory damage to the hand? Which part of hand?
Wrist drop is due to the extensors in the posterior forearm being damaged - e.g. extensor carpi radialis longs
Triceps brachia weakened not paralysed
Cutaneous branches to arm and forearm are more proximal.
Cutaneous branch to hand affects the dorsal side lateral 31/2 digits and the associated dorsum of hand.
Why would a stab/laceration to the forearm affecting the radial nerve not lead to wrist drop?
Because the motor branch for extensor carpi radialis longus has already arisen so maintains some extension at the wrist.
Other extensors get wiped.
Which cords does the median nerve arise from in the brachial plexus?
medial and lateral
Which cord does the radial and axillary nerves arise from?
posterior
Which cord does the musculocutaneous nerve arise from?
lateral
Which cord does the ulna nerve arise from?
medial
Which nerve runs through the carpal tunnel?
Median nerve
How could you test for carpal tunnel type pain/sensations? Where might you feel pain/parasthaesia?
Flexion at the wrist for 60secs may produce pain or parasthaesia in the median nerve distribution (lateral 3.5 digits, thenar eminence, tips of fingers, and associated palm)
What is the hand of Benediction?
Median nerve injury at the elbow or wrist may cause this e.g. lacerations.
Thenar muscles paralysed and lateral 2 lumbricals
Sensory loss of lateral 3.5 digits and tips of fingers, thenar eminence and associated palm
Ask to make a fist will make the Hand of benediction
Which nerve supplies the flexors of the anterior compartment of the forearm apart from the flexor carpi ulnaris and medial half of flexor digitorum profundus?
Median
What muscles does the ulnar nerve innervate?
Most of the muscles of the hand except the lateral two lumbricals, the thenar muscles, flexor carpi radialis and the lateral half of the flexor digitorum profundus
Where is the ulnar nerve most susceptible to damage?
Medial epichondyle
What happens with damage to the ulnar nerve at the wrist vs elbow?
Wrist - medial 2 lumbricals paralysed, interossei are paralysed so no flexion or abduction/adduction of those digits gives a claw. Unopposed extension at the MCP, unopposed flexion as DIP from FDP.
At the elbow the flexor carpi ulnaris and medial 1/2 of flexor digitorum profundus are also paralysed so claw looks less severe but more muscles are paralysed - paradox.
Why is brachioradialis an exception of the posterior compartment of the forearm?
It origin and innervation are characteristic of extensors but it is a flexor.
Radial nerve
Flexes elbow in the 1/2 pronated 1/2 supinated position - so assists in pronating/supinating (beer drinking)
What do extensors of the wrist/fingers help with?
Improves grip