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There are three flexors and three extensors for the wrist joint.

The wrist flexors are:

1. Flexor carpi radialis: It originates from the medial epicondyle of humerus (common flexor tendon) and inserts in second and third metacarpal bones. Along with flexion radial abduction at wrist.
2. Flexor carpi ulnaris: which originates from medial epicondyle (common flexor tendon) and inserts in pisiform. it also helps in ulnar abduction.
3. Palmaris longus: Like the other two it also originates fro, the medial epicondyle (common flexor tendon) but inserts in palmar epineurosis.

The wrist extensors are:

1. Extensor carpi radialis longus: this muscle originates from lateral supracondylar ridge and inserts into the second metacarpal.
2. Extensor carpi radialis brevis: originates from the humerus at the anterior of lateral epicondyle (common extensor tendon) and inserts into base of third metacarpal.
3. Extensor carpi ulnaris: originates from common extensor tendon lateral epicondyle, ulna. And inserts into 5th metacarpal.

The main elbow flexors are:

1. Biceps brachii: A muscle with two heads or points of origin.
2. Brachialis A strong muscle lying immediately below the biceps brachii in the upper arm. Its origin is on anterior lower half of humerus and it inserts onto the anterior coronoid process of the ulna. Its primary action is elbow flexion, especially when the forearm is midway between full flexion and full extension.
3. Brachioradialis: The muscle of the arm that flexes the elbow joint, origin is the lateral supracondylar ridge of the humerus, and insertion is the lower end of the radius.

The main extensor of elbow joint is:

1. Triceps brachii: A large fleshy muscle at the back of the arm. It is commonly reffered to as the triceps. It opposes the action of biceps by straightening the arm. This three headed muscle originates from the humerus and the shoulder blade. A single tendon inserts the three heads of the muscle onto the olecranon process, the prominent protection of the ulna in the elbow. This tendon is easily damaged by forceful throwing or when falling on the hand with a fully extended arm.
2. Aconeus: A very small muscle assists in extension of the elbow joint.