[Isolated compression of the dorsal branch of the ulnar nerve].

The dorsal branch of the ulnar nerve was dissected in 20 upper extremities. The nerve arises from the ulnar aspect of the ulnar nerve at an average distance of 8.5 centimeters from the proximal border of the pisiforme. It courses deep to the palmar carpal ligament and pierces the ligament dorsal to the tendon of the flexor carpi ulnaris, becoming subcutaneous. The palmar carpal ligament has been found to be a cause of isolated entrapment of the dorsal branch of the ulnar nerve. A report of eleven operative cases is presented.