The flexor carpi radialis runs from the medial epicondyle to the base of the index finger metacarpal, passing through a dedicated fibro-osseous tunnel at the wrist adjacent to the trapezium rather than through the main carpal tunnel. Its tendon is one of the most prominent wrist landmarks, identifiable just medial to the radial artery pulse, and it is the most frequently harvested wrist flexor tendon in reconstructive surgery because of its accessibility and expendability.
| Origin | Medial epicondyle via the common flexor tendon |
|---|---|
| Insertion | Base of the second metacarpal with a small slip to the third |
| Nerve Supply | Median nerve (C6, C7) |
| Blood Supply | Radial artery |
| Actions | Flexion of the wrist; Radial deviation of the wrist; Weak assistance in forearm pronation |
|---|
Its combined flexion and radial deviation action is important during the acceleration phase of racket sport swings and in any activity requiring simultaneous wrist flexion and radial movement, such as hammering or throwing.
FCR tendinopathy produces radial-sided wrist pain at the base of the thenar eminence reproduced by resisted wrist flexion with radial deviation, and must be distinguished from scaphoid pathology, de Quervain tenosynovitis, and first carpometacarpal arthritis before treatment begins. Stenosis of the FCR tunnel adjacent to the scaphoid-trapezoid joint is an underrecognised cause of chronic radial wrist pain in middle-aged and older patients.
The FCR tendon is the prominent cord just medial to the radial artery pulse at the volar wrist crease, standing out clearly during resisted wrist flexion with radial deviation and easily distinguished from the palmaris longus tendon by its more lateral position.
Degenerative overuse at the wrist producing radial-sided wrist pain reproduced by resisted wrist flexion and radial deviation, managed with activity modification and graduated loading.
Stenosis of the fibro-osseous tunnel adjacent to the trapezoid producing chronic radial wrist pain worsening with wrist extension and gripping, requiring surgical release in persistent cases.
