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

What arches of the hand are typically lost in Claw Fingers Deformity?

1. Proximal Transverse and Distal Transverse

2. Longitudinal and Radial

3. Proximal Transverse and Longitudinal

4. Distal Transverse and Palmar

The correct answer is: Proximal Transverse and Distal Transverse

The correct response highlights the loss of the Proximal Transverse and Distal Transverse arches of the hand in the context of Claw Fingers Deformity. In Claw Fingers Deformity, the fingers exhibit a hyperextension at the metacarpophalangeal joints while simultaneously curling at the interphalangeal joints, resembling a claw. This deformity is associated with neurological considerations, particularly the ulnar nerve, which innervates the intrinsic muscles of the hand that are essential for maintaining the arches. The Proximal Transverse arch runs across the proximal row of carpal bones and is vital for the stability of the hand. The Distal Transverse arch, formed by the metacarpal heads, allows for a grasping function of the fingers. The loss of both these arches contributes to the structural instability and functional deficits observed in claw hand presentations. While other arches, such as the Longitudinal and Radial arches, are important for hand function, the characteristic posture and deficits seen in Claw Fingers Deformity specifically indicate a loss of the Proximal Transverse and Distal Transverse arches, making this choice the most relevant in understanding the functional impairment associated with the condition.