Ulnar nerve

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Nerve: Ulnar nerve
Click image to enlarge - ulnar nerve is visible in lower left
Nerves of the left upper extremity. (Ulnar labeled at center left.)
Latin Nervus ulnaris
Gray's subject #210 943
Innervates flexor carpi ulnaris
flexor digitorum profundis
lumbrical muscles
opponens digiti minimi
flexor digiti minimi
abductor digiti minimi
interossei
adductor pollicis
From Medial cord
Dorlands/Elsevier n_05/12566994

In human anatomy, the ulnar nerve is a nerve which runs from the shoulder to the hand, at one part running near the ulna bone. It is the only exposed nerve in the human body (it is unprotected for a few centimeters at the elbow).

Contents

[edit] Course

The ulnar nerve comes from the medial cord of the brachial plexus, and runs inferior on the medial/posterior aspect of the humerus down the arm, going behind the medial epicondyle at the elbow. Because of the mild pain and tingling throughout the forearm associated with an inadvertent impact of the nerve at this point, it is sometimes called the funny bone. (It may also have to do with its location relative to the humerus, as well as the fact that "humerus" is homophonic to the word "humorous").

It enters the anterior (front) side of the forearm, and runs alongside the ulna. There it supplies one and a half muscles (flexor carpi ulnaris & medial half of flexor digiti profundus). It soon joins with the ulnar artery, and the two travel inferiorly together, deep to the flexor carpi ulnaris muscle.

After its journey down the ulna, the ulnar nerve enters the palm of the hand. Unlike the median nerve which travels below the flexor retinaculum of the hand and through the carpal tunnel, the ulnar nerve and artery pass superficial to the flexor retinaculum via the ulnar canal.

[edit] Branches and innervation

[edit] Muscular

The ulnar nerve and its branches innervate the following muscles in the forearm and hand:

[edit] Cutaneous

The ulnar nerve also provides sensory innervation to the part of the hand corresponding to the fourth and fifth digits:

[edit] See also

[edit] Additional images

[edit] External links

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