Question

A lesion of the ulnar nerve at Guyon's canal, before it splits into the superficial and deep branch, will NOT cause the following:

a) Weakness of intrinsic hand muscles
b) Sensory loss in the ulnar distribution
c) Claw hand deformity
d) Weakness of wrist flexors

Answer 1

A lesion at Guyon's canal, before it splits into branches, will not cause claw hand deformity or weakness of intrinsic hand muscles and wrist flexors, but may cause sensory loss in the ulnar distribution.

Step-by-step explanation:

A lesion of the ulnar nerve at Guyon's canal, before it splits into the superficial and deep branch, will not cause claw hand deformity. The claw hand deformity is caused by a lesion at the level of the ulnar nerve where it innervates the ulnar-innervated intrinsic hand muscles.

In a lesion at Guyon's canal, the ulnar nerve will still be able to innervate the intrinsic hand muscles and the wrist flexors, so weakness of these muscles will not occur. However, there may be sensory loss in the ulnar distribution since the ulnar nerve carries sensory information from the ulnar side of the hand.