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

Adduction

Adduction is a movement which brings a part of the anatomy closer to the middle sagittal plane of the body. It is opposed to abduction.-Upper limb:* of arm at shoulder ** Subscapularis** Teres major** Pectoralis major** Infraspinatus...

 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

Ulnar nerve

In human anatomy, the ulnar nerve is a nerve which runs near the ulna bone. The ulnar collateral ligament of elbow joint is in relation with the ulnar nerve. The nerve is the largest unprotected nerve in the human body , so injury is common...

 and ulnar artery

Ulnar artery

The ulnar artery is the main blood vessel, with oxygenated blood, of the medial aspect of the forearm. It arises from the brachial artery and terminates in the superficial palmar arch, which joins with the superficial branch of the radial artery...

 pass.

• The humeral head arises from the medial epicondyle
  Medial epicondyle
  Medial epicondyle can refer to:* Medial epicondyle of the humerus * Medial epicondyle of the femur...
  
   of the humerus
  Humerus
  The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
  
   by the common flexor tendon.
• The ulnar head arises from the medial margin of the olecranon
  Olecranon
  The olecranon is a large, thick, curved bony eminence of the forearm that projects behind the elbow.It is situated at the upper end of the ulna, one of the two bones in the forearm...
  
   of the ulna
  Ulna
  The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form and runs parallel to the radius, which is shorter and smaller. In anatomical position The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form...
  
   and from the upper two-thirds of the dorsal border of the ulna by an aponeurosis
  Aponeurosis
  Aponeuroses are layers of flat broad tendons. They have a shiny, whitish-silvery color, are histologically similar to tendons, and are very sparingly supplied with blood vessels and nerves. When dissected, aponeuroses are papery, and peel off by sections...
  
  .

Its insertion is into the pisiform bone and then via ligaments into the hamate bone and 5th metacarpal bone, acting to flex and adduct the wrist joint.

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. Flexor carpi ulnaris is the most medial (closest to the little finger) of these. (The most lateral one is flexor carpi radialis muscle

Flexor carpi radialis muscle

In anatomy, flexor carpi radialis is a muscle of the human forearm that acts to flex and abduct the hand.-Origin and insertion:This muscle originates on the medial epicondyle of the humerus...

, and the middle one, if it exists, is palmaris longus.)

Exercises

The muscle, like all flexors of the forearm, can be strengthened

Strength training

Strength training is the use of resistance to muscular contraction to build the strength, anaerobic endurance, and size of skeletal muscles. There are many different methods of strength training, the most common being the use of gravity or elastic/hydraulic forces to oppose muscle contraction...

 by exercises that resist its flexion. A wrist roller

Wrist roller

The wrist roller is a device designed for strengthening the wrists together in a rolling-pulling motion. It consists of a bar of varying lengths, with a cord or rope attached, which the user rolls and unrolls. This is resisted by the weight of a mass at the bottom of the cord. Rolled and unrolled,...

 can be used and wrist curls with dumbbell

Dumbbell

The dumbbell, a type of free weight, is a piece of equipment used in weight training. It can be used individually or in pairs .-History:...

s 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 2 heads of the flexor carpi ulnaris (FCU) muscle may cause cubital tunnel syndrome.