A young man develops weakness of his right hand and describes an incident in which he grabbed onto a tree branch to brake a fall when hiking. He has normal range of movement at the shoulder, elbow and wrist but cannot use precision or power grip. What structure is likely to have been damaged?
1.The radial nerve
2.The ulnar nerve
3.The T1 nerve root
4.The C7 nerve root
5.The axillary nerve
Explanation:
This man has Klumpkes paralysis in which brachial plexus injury to C8 and/or T1 affects the forearm and hand. The most common cause is difficult childbirth, although any stretching of the arm may cause it. It is characterised by a claw hand, forearm supination, hyperextension of the fingers and weak grip.