College of Massage Therapists of British Columbia (CMTBC) Practice Exam

Which two nerves are primarily involved in Claw Fingers Deformity?

1. Ulnar Nerve and Median Nerve

2. Radial Nerve and Ulnar Nerve

3. Median Nerve and Musculocutaneous Nerve

4. Median Nerve and Radial Nerve

The correct answer is: Ulnar Nerve and Median Nerve

Claw fingers deformity, characterized by the hyperextension of the metacarpophalangeal joints and flexion of the interphalangeal joints, involves the dysfunction of specific nerves that control the muscles necessary for hand function. The ulnar nerve and the median nerve play crucial roles in this condition. The ulnar nerve primarily innervates the intrinsic muscles of the hand, including the interossei and the ulnar half of the flexor digitorum profundus. When this nerve is compromised, the muscles it innervates can become weak or paralyzed, leading to the inability to extend the fingers properly at the metacarpophalangeal joints, culminating in the claw-like appearance. The median nerve also contributes to the muscle function of the hand, particularly the thenar muscles and the radial two lumbricals. If this nerve is affected, it can impact finger flexion and coordination, further exacerbating the claw-like deformity. The combination of impairments in both the ulnar and median nerves leads to the classic presentation of claw fingers, making it clear why these two nerves are primarily associated with the condition. Other nerves listed in the choices, such as the radial and musculocutaneous nerves