The ulnar nerve is one of the main branches of the medial cord of the brachial plexus. It provides innervation to the majority of the intrinsic hand muscles and sensation to the medial hand and the medial one-and-a-half fingers. An injury to the ulnar nerve causes inability to extend the interphalangeal joints of the medial two fingers, hypothenar atrophy, and atrophy of the first dorsal interosseous space. Primary repair vs. grafting of the ulnar nerve could restore some function; however, the prognosis is poor, especially in more proximal injuries. Anterior interosseous nerve (AIN) to ulnar motor nerve transfer end-to-end vs. end-to-side can provide additional benefit to patients with severe ulnar neuropathy.