Flexor carpi ulnaris muscle

Flexor carpi ulnaris
Dorsal (left) and ventral (right) views of deep muscles of the forearm. FCU is visible in blue.
Details
Latin	Musculus flexor carpi ulnaris
Origin	Medial epicondyle (common flexor tendon) and medial margin on olecranon of ulna
Insertion	Pisiform, hook of the hamate, base of the fifth metacarpal bone
Artery	Ulnar artery
Nerve	Muscular branches of ulnar nerve
Nerve root	C7, C8 and T1
Actions	Flexion and adduction of wrist
Antagonist	Extensor carpi radialis brevis muscle and extensor carpi radialis longus muscle
Identifiers
Dorlands /Elsevier	m_22/12549030
TA
TH	{{#property:P1694}}
TE	{{#property:P1693}}
FMA	{{#property:P1402}}
Anatomical terms of muscle [[[d:|edit on Wikidata]]]

The flexor carpi ulnaris muscle (or FCU) is a muscle of the human forearm that acts to flex and adduct (medial deviation) the hand.

Origin and insertion

Flexor carpi ulnaris muscle arises by two heads, humeral and ulnar, connected by a tendinous arch beneath which the ulnar nerve and artery pass.

• The humeral head arises from the medial epicondyle of the humerus by the common flexor tendon.
• The ulnar head arises from the medial margin of the olecranon of the ulna and from the upper two-thirds of the dorsal border of the ulna by an aponeurosis.

Its insertion is into the pisiform bone and then via ligaments into the hamate bone-g pisohamate ligament- and 5th metacarpal bone-forming pisometacarpal ligament. Its action is to flex and adduct the wrist joint.

Innervation

The FCU is innervated by the ulnar nerve which has its roots in the C7, C8 and T1 spinal nerves.

Tendon

The tendon of flexor carpi ulnaris can be seen on the anterior of the distal forearm. On a person's distal forearm, right before the wrist, there will be either two or three tendons. The tendon of the flexor carpi ulnaris is the most medial (closest to the little finger) of these. The most lateral one is the tendon of flexor carpi radialis muscle, and the middle one, not always present, is the tendon of palmaris longus.

Exercises

The muscle, like all flexors of the forearm, can be strengthened by exercises that resist its flexion. A wrist roller can be used and wrist curls with dumbbells can also be performed. These exercises are used to prevent injury to the ulnar collateral ligament of elbow joint.

Disease

Ulnar entrapment by the aponeurosis of the two heads of the flexor carpi ulnaris (FCU) muscle may cause cubital tunnel syndrome.

Additional images

• 

  Bones of left forearm. Posterior aspect.

• 

  Bones of the left hand. Volar surface showing its insertion into the pisiform bone and then via ligaments into the hamate bone and 5th metacarpal bone, acting to flex and adduct the wrist joint.

• 

  Cross-section through the middle of the forearm.

• 

  Flexor carpi ulnaris muscle

External links

• Illustration: upper-body/flexor-carpi-ulnaris from The Department of Radiology at the University of Washington