A patient with an ulnar nerve injury may present with which hand appearance?

In the case of an ulnar nerve injury, the characteristic presentation known as "claw hand" occurs due to the dysfunction of the intrinsic muscles of the hand, primarily responsible for the movement of the fingers. The ulnar nerve innervates many of these intrinsic muscles, including the interossei and the ulnar half of the flexor digitorum profundus. When the ulnar nerve is compromised, it results in the inability to fully extend the fourth and fifth digits at the proximal interphalangeal joints, while the metacarpophalangeal joints may become hyperextended due to the unopposed action of the extensor muscles. This causes the fingers to flex at the proximal joints and extend at the distal joints, leading to the classic clawing appearance.

Additionally, other choices, though related to hand appearance or function, do not accurately represent the clinical presentation associated with an ulnar nerve injury. Wrist drop, for instance, refers to radial nerve injury resulting in an inability to extend the wrist and fingers. Thumb adduction may suggest issues with thumb function but is not specific to an ulnar nerve injury, as it can occur in various conditions. Lastly, a flat hand could indicate other muscular