Flexor Carpi Ulnaris Muscle Pain

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Written By Dr. Marcus Yu Bin Pai

MD, PhD. Physical Medicine & Rehabilitation Physician from São Paulo - Brazil. Pain Fellowship in University of São Paulo.


The pain felt in the ulnar region of the wrist is flexor carpi ulnaris discomfort. These symptoms may be made worse by particular movements or positions and lessened by rest. When doing repetitive activities like typing or rowing, it is typically brought on by incorrect wrist alignment.

An issue with the flexor carpi ulnaris muscle may be the source of pain on the ulnar side of the wrist that goes away with rest.

Muscular Anatomy


The superficial forearm flexor muscle known as the “flexor carpi ulnaris” is responsible for flexing and adducting the hand. This wrist flexor has the maximum strength.

The fusiform flexor carpi ulnaris muscle is situated in the anterior forearm compartment. Along with pronator teres, palmaris longus, flexor digitorum superficialis, and flexor carpi radialis, it is a member of the superficial flexors of the forearm. The medialmost of the superficial flexors is the flexor carpi ulnaris.


The flexor carpi ulnaris has two independent heads joined by a tendinous arch. While the ulnar head develops from the olecranon and the top third of the ulna’s subcutaneous border by an aponeurosis, the humeral head develops from a flexor tendon origin on the medial epicondyle.


The fifth metacarpal bone, the hook of the hamate, and the pisiform bone of the wrist are where the flexor carpi ulnaris enters. The flexor carpi ulnaris enters into the 5th metacarpal bone through the pisometacarpal ligament and into the hook of the hamate through the pisohamate ligament.

Nerve Supply

The muscular branch of the ulnar nerve, represented by C7 and C8, innervates the flexor carpi ulnaris.

Blood Supply

The tiny ulnar artery branches and ulnar collateral arteries supply the flexor carpi ulnaris.

Functions of Flexor Carpi Ulnaris Muscle

Flexor carpi ulnaris flexes the hand at the wrist in conjunction with other anterior forearm muscles. The flexor carpi ulnaris not only helps the hand to flex, but it also helps the hand to adduct at the wrist. Last but not least, it helps with finger flexion.

Causes of Flexor Carpi Ulnaris Muscle pain


A person may suffer discomfort in their flexor carpi ulnaris muscle for various causes. The most prevalent cause is repetitive strain, which occurs when a muscle is continually tightened to maintain a specific posture. Repetitive strain may occur in athletes and individuals performing repetitive work duties.

An injury can also cause pain in the muscle or joint that connects to the arm. When a person has an injury, edema can form around and inside the joint, increasing pressure. This puts too much strain on the fascia, causing blood vessels and nerve endings to compress and cause discomfort.

Trigger Points of Flexor Carpi Ulnaris muscle

Trigger points are tiny, knotted areas of muscular tissue. They form when a muscle does not relax and gets tight, generally due to repeated usage or trauma.

The technique of releasing (or deactivating) trigger points can be accomplished by self-massage or by applying pressure to them using a foam roller. Self-massage methods include applying deep pressure to the trigger point with one’s fingers, thumbs, or knuckles.

If no weight bearing is available, or if one is disabled or too exhausted to use their hands for self-massage, the foam roller is frequently utilized.

Pain Patterns and Symptoms

When your flexor carpi ulnaris is too tight or has trigger points, it might cause discomfort on your wrist’s ulnar/outer side. Additionally, the pain may spread to your forearm and hand.

If your flexor carpi ulnaris hurts, you may have difficulty bending and flexing your hand and fingers. It might get so terrible that even carrying a cup of coffee becomes difficult.


One of the most intricate muscles in hand is the flexor carpi ulnaris muscle. It inserts into the base of the fifth metacarpal bone and originates from the medial epicondyle of the humerus. The muscle essentially controls the supination of the thumb’s MCP joints and wrist flexion.

This muscle can be injured, an uncommon event, and is the most frequent cause of flexor carpi ulnaris muscle discomfort. This might occur when playing a sport like tennis or baseball, or even while doing a routine task like reaching into a high cabinet or carrying something heavy with your arms out in front of you. This injury is also susceptible to repetitive strain, mainly if you work with your hands and wrists in a lot of twisting, bending, and stretching activities.

It is suggested that you rest your arm for a few days and utilize ice treatment or prescription medication if necessary to reduce wrist muscle discomfort. If the symptoms didn’t go away after home treatment, we strongly recommend you see your doctor.

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MD, PhD. Physical Medicine & Rehabilitation Physician from São Paulo - Brazil. Pain Fellowship in University of São Paulo.

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