Flexor carpi radialis

On a muscle model of the arm, the flexor carpi radialisFlexor / Abductor Front of forearm; bends wrist and moves hand toward thumb side. is located on the anteriorThe front of the body or toward the front when standing in the anatomical position. (palm-side) forearm. It is just lateralAway from the midline of the body. to the palmaris longusFlexor Front and inner side; bends wrist and moves hand toward pinky side. (if present). It starts from the medial epicondyleProminent bump on distal medial side; attachment for forearm muscles (“funny bone”). of the humerusLong bone of the upper arm; articulates with scapula at shoulder and radius/ulna at elbow.. It runs diagonally across the forearm. It inserts on the bases of the 2nd and 3rd metacarpalsPalm bones numbered thumb (1) to pinky (5); heads form knuckles.. On models with color-coded tendons, look for its tendon crossing the wrist toward the thumb side. It may appear more prominent or thickened. The palmaris longus has a longer and thinner tendon. Sometimes it isn’t even present.

Turning a doorknob or using a screwdriver is a common everyday action that requires the flexor carpi radialis. Any activity that involves wrist flexion and radial deviation (bending the wrist toward the thumb side) uses this muscle. One example of overuse is typing or using a computer mouse for long hours without wrist support. Another is repetitive gripping and lifting, like carrying grocery bags with a bent wrist. These motions can strain the tendon and lead to discomfort. They may also cause conditions like tendinitis if the muscle is not given adequate rest.

Origin

Medial epicondyle of the humerus (via the common flexor tendon)

Insertion

Bases of the 2nd and 3rd metacarpal bones

Actions

Flexes and abducts the wrist (radial deviation)