There are flexors and extensors that enables the wrist to move.
The flexors flexor carpi radialis and flexor carpi ulnaris that emerge from the medial epicondyle share the common flexor tendon. The flexor carpi also arises from the border of the ulna. The two diverge and land at the radial and ulnar side of the wrist. The two flexors act to produce flexion of the wrist. The third flexor—the palmaris longus, also emerging from the medial epicondyle, also assists in wrist flexion as it’s tendon lies deep within the superficial soft tissue of the palm (palmar aponeurosis).
There are three extensors: extensor carpi radialis,extensor radialis brevis and extensor carpi ulnaris. Extensor carppi radialis longus and extensor radialis brevis originate from the lateral epicondyle and shares a common tendon. Extensor carpi ulnaris emerge from the border of the ulna. The extensor tendons intersect at the back of the wrist as it passes through the extensor retinaculum. The extensor retinaculum serve as a pulley so that when the extensors move together, the wrist can be extended.
The muscles that flex the wrist are three: the flexor carpi radialis, and flexor carpi ulnaris they originate in the medial epicondyle and then they diverge to arrive at the radial and ulnar sides of the wrist. The flexor carpi radialis ends on the second metacarpal. Flexor carpi ulmaris, end in the fifth metacarpal. The third flexor is the palmaris longous, which is in between the two flexors and originates in the medial epicondyle and is inserted in the palmar fascia.
On the other side of the forearm, we have the three extensors, which are, extensor carpi radialis longus, extensor carpi radialis brevis, and extensor carpi ulnaris. They all arise together from the epicondyle and the common extensor tendon. Extensor carpi radialis longus and brevis are inserted on the bases of the second and third metacarpals, while extensor ulnaris on the base of the fifth metacarpal.
