The flexor carpi radialis is a long, flat and bipennate muscle. It lies on the antero-lateral aspect of forearm, laterally to all the other flexor muscles. It arises from the medial epicondyle of humerus and the antebrachial fascia. Then it travels downwards, running slightly obliquely as it stretches over to the radial side of forearm, covering the proximal portion of flexor digitorum profundus and flexor pollicis longus muscle.
In the distal portion of forearm, the flexor carpi radialis muscle ends up in a strong tendon which runs under the flexor retinaculum, by the side of the carpal tunnel (it does not pass through it). It is inserted into the base of the palmar surface of the second and third metacarpal bone. Proximally, it is covered by the aponeurosis of the biceps brachii and the palmaris longus muscle, while its remaining part is covered by fascia and skin.
Action
The flexor carpi radialis flexes the wrist (and hand) towards the radial bone.
Innervation
It is innervated by the median nerve (C6-C7), which arises from the brachial plexus.
Blood Supply
This forearm muscle is supplied by muscular branches of the radial artery.
Below, superficial muscles of the anterior side of forearm, showing the
