An injury to the ulnar nerve can lead to which of the following conditions?

Injury to the ulnar nerve can lead to the condition known as claw hand. This condition occurs because the ulnar nerve is responsible for innervating many of the intrinsic muscles of the hand, particularly those involved in finger movement and fine motor control. When the ulnar nerve is damaged, the result can be a loss of function in the affected muscles, leading to an imbalance in the musculature of the hand. This imbalanced state causes the fingers to adopt a claw-like posture, characterized by hyperextension of the proximal interphalangeal joints and flexion at the distal joints.

The other conditions associated with nerve injuries are related to different nerves. For instance, wrist drop is caused by radial nerve injury, resulting in the inability to extend the wrist. Erb's palsy involves injury to the upper trunk of the brachial plexus affecting shoulder abduction and elbow flexion. Foot drop is associated with a peroneal nerve injury, leading to the inability to dorsiflex the foot. Understanding these distinct nerve functions helps clarify why claw hand specifically results from ulnar nerve damage.