Radial nerve anatomy and palsy

Question 1

Anatomy

Answer 1

o Arises in the axilla behind axillary artery
o Out via the triangular interval
o Down the arm via the radial groove of the humerus
o As it travels down humerus it is accompanied by the brachial artery
o Enters the forearm anterior to the lateral epicondyle of humerus through the cubital fossa
o In forearm divides into superficial and deep branch.

Question 2

Motor function

Answer 2

oTriceps brachii : extends the arm at the elbow

oExtensor muscles of the FOREARM via the deep branch : extend the wrist and finger joints, supinates the forearm

Question 3

Sensory function

Answer 3

o Skin on the posterior side of forearm
o Dorsal side of the lateral aspect of the arm
o Dorsal surface of 3 and a half digits

Question 4

Roots?

Answer 4

C5-T1

Question 5

Aetiology of palsy?

Answer 5

1. Fracture humeral shaft
2. Saturday Night Palsy- drunk person falls asleep with harm behind chair- can compress radial nerve.
3. Honeymoon Palsy- when other people fall asleep on their partners arm
4. Crutch Palsy- when walking on crutches

Question 6

What will be the presentation If the damage is in the axilla?

Answer 6

• Loss of extension of arm at elbow
• Loss of forearm supination
• Wrist drop
• Sensory loss

Question 7

What will be the presentation if the damage is at the wrist?

Answer 7

-sensory loss

Question 8

What will be the presentation if the damage is at elbow?

Answer 8

• Wrist drop

- Sensory loss

Question 9

What will be the presentation if damage is at forearm?

Answer 9

• Loss of finger extension

- Sensory loss