Lab3 - Module 2 - Anatomy of the Arm and Forearm: Page 9 of 11

Anterior Nerves of the Forearm

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Add the Ulnar Nerve which passes posterior to the medial epicondyle of the humerus, the ulnar nerve enters the forearm by passing between the two heads of the flexor carpi ulnaris muscle. It descends deep to this muscle on the flexor digitorum profundus where it accompanies the ulnar artery near the middle of the forearm. It becomes relatively superficial in the distal part of the forearm. Near the pisiform bone it pierces the deep fascia and passes superficial to the flexor retinaculum. The branches of the ulnar nerve are:

The Articular branches to the elbow joint.

The Muscular branches to supply flexor carpi ulnaris and the medial half of the flexor digitorum profundus.

The Superficial branch (palmar cutaneous branch) supplies the skin of the medial palm and medial 1 ½ digits.

The Dorsal cutaneous branch supplies the posterior surface of the medial part of the hand and medial 1 ½ digits.

Ulnar Nerve Injury may result in extensive motor and sensory loss to the hand. Patients may have difficulty in making a fist due to inability to flex their fourth and fifth digits at the distal interphalangeal joints. The appearance of the hand is then known as claw hand.

	Is the Ulnar nerve effected by a Carpal Tunnel Syndrome?
Near the pisiform bone it pierces the deep fascia and passes superficial to the flexor retinaculum. Therefore it does not pass through the Carpal Tunnel