Certified Hand Therapist (CHT) Exam 2025 – 400 Free Practice Questions to Pass the Exam

The characteristic deformity associated with radial nerve palsy is the inability to extend the wrist and fingers, commonly referred to as "wrist drop." This condition occurs due to paralysis or weakness of the muscles responsible for extending the wrist and fingers, which are innervated by the radial nerve. As a result, the patient presents with the wrist flexed and fingers flexed at the metacarpophalangeal joints, leading to a characteristic appearance where the hand hangs limp at rest.

In contrast, the other options describe different conditions or deformities associated with other nerve injuries. Claw hand is typically seen in ulnar nerve palsy, while ulnar deviation of the wrist can be associated with conditions like rheumatoid arthritis or dysfunctions of the wrist and hand, not specifically with radial nerve palsy. Lastly, thumb adduction and opposition pertain to median nerve injuries, which cause deficits in thumb function but do not directly relate to the wrist drop seen in radial nerve palsy. Thus, the hallmark sign of wrist drop distinctly identifies the effects of radial nerve dysfunction.