Long Ulnar Digital Nerve Exam

In patient's with lacerations, sensation is assessed by examining light touch and/or two point discrimination.
The digital nerves are derived from the median and ulnar nerves.
The radial common digital nerve of the median nerve branches to the digital nerves of the thumb and radial side of the index.
The 2^nd common digital nerve from the median nerve branches into the ulnar digital nerve of the index and radial digital nerve of the long.
The 3^rd common digital nerve of the median nerve branches into the ulnar digital nerve of the long and radial digital nerve of the ring.
The common digital nerve of the 4-5 web from the ulnar nerve branches into the ulnar digital nerve of the ring and radial digital nerve of the little, while the ulnar nerve provides the ulnar digital nerve of the little.

Diagrams & Photos

Testing light touch distal to a laceration. Note patient's eyes are closed.
Testing two point discrimination distal to a laceration.
Anterior (palmar or volar) Sensation by Nerve: 1 = median nerve; 2 = dorsal radial sensory nerve; 3 = ulnar nerve; 4 = lateral antebrachial cutaneous nerve; 5 = medial antebrachial cutaneous nerve; 6 = radial dorsal antebrachial cutaneous nerve; 7 = medial brachial cutaneous nerve; 8 = intercostobrachial nerve; 9 = axillary nerve (superior lateral brachial cutaneous nerve.
Motor, sensory and triceps reflex exam for C6 Root
Note severe anhydrous of skin due to denervation of the sweat glands.

Key Points

The digital nerve trifurcates at the middle of the middle phalanx and sends branches dorsally to provide sensation over the dorsal DIP joint area and distal dorsal fingertip.
The digital nerves lie palmar (superficial) to the arteries in the finger and dorsal (deep) to the common digital arteries in the palm.