Definition

By: Gregory R. Waryasz, MD

The flexor carpi ulnaris muscle of the musculoskeletal system is characterized by being two heads; a humeral and an ulnar head.  It is innervated by the ulnar nerve.

It is part of the forearm.  It consists of skeletal muscle fibers.

Its unique structural features include its humeral and ulnar head.  The flexor carpi ulnaris is the most medial of the superficial flexor muscles.  The ulnar nerve passes between the humeral and ulnar heads.  The distal portion is tendinous.

The common proximal attachment of all the superficial flexor-pronator muscles is the common flexor tendon to the medial epicondyle of the humerus.

The origin of the humeral head is the medial epicondyle of the humerus.  The origin of the ulnar head is the olecranon and posterior border by the aponeurosis.

The insertion is the pisiform, hook of the hamate, and the 5th metacarpal.

The blood supply is from the ulnar artery and venous drainage is from the accompanying veins.

The innervation is from the ulnar nerve.

The flexor carpi ulnaris muscle as well as all other bones, muscles, and ligaments of the body are derived of mesodermal origin in the embryo.

The function of the flexor carpi ulnaris is to flex and adduct the hand at the wrist.  It works synergistically with the flexor carpi radialis.  The flexor carpi ulnaris helps to protect the ulnar nerve and artery at the wrist.

Common diseases include tendon rupture, tenosynovitis, and calcific tendinitis.

Tendon rupture can occur with trauma.

Tenosynovitis of the flexor carpi ulnaris is associated with repetitive trauma.  There is tenderness over the tendon at the wrist and at the pisiform.  Tenderness and pain can be present with wrist flexion.

Calcific tendinitis can occur at the insertion into the pisiform.

Commonly used diagnostic procedures include clinical history, physical exam, and MRI.

It is usually treated with rest, NSAIDs, physical therapy, splinting, and corticosteroid injection for tenosynovitis.  Tendon rupture may require surgery.

References

Lieberman J (ed), AAOS Comprehensive Orthopaedic Review, American Academy of Orthopaedic Surgeons, 2008.

Moore K, Dalley A (eds), Clinically Oriented Anatomy (5th edition), Lippincott Williams & Wilkins, Philadelphia, PA, 2006.

Wheeless’ Textbook of Orthopaedics: Flexor Carpi Ulnaris (http://www.wheelessonline.com/ortho/flexor_carpi_ulnaris)