Radial nerve

Question 1

Site of impingement

Answer 1

1 of 3 sites:
– triangular space, radial groove and elbow

Question 2

Triangular space

Answer 2

Between- teres major, triceps (long head) and humerus

can be due to:
– poor adjusted crutches
– humeral fractures and dislocations
– falling asleep with an arm over the chair (Saturday night palsy)

Signs and symptoms:
– weakness of elbow extension
– weakness of wrist extension and wrist drop
– loss of triceps reflex
– loss of sensation to entire posterior arm and forearm (except lateral forearm, as its supplied by the musculocutaneous nerve)
– loss of sensation to posterior lateral fingers 3.5 to DIP joints

Question 3

Radial groove

Answer 3

Often due to:
– compression from humeral fractures
– tourniquets or blood pressure cuffs
– entrapment below triceps brachia muscle

Signs and symptoms:
– weakness of wrist extension and wrist drop
– loss of sensation to posterior lateral 3.5 fingers to DIP joints

Question 4

Elbow

Answer 4

Deep branch of the radial nerve is compressed by fractures of proximal radius or as it passes through the 2 planes of the supinator muscle

Compression can also occur by the extensor carpi radialis brevis muscle (less common)

Signs and symptoms:
– weakness of thumb and MCP extension