The extensor digitorum is located in the back of the forearm. It contributes to pain in the back of the hand and middle finger which sometimes radiates up into the back of the wrist and the back of the forearm. Pain is occasionally felt in the front of the wrist, just below the palm.
The pronator teres muscle is located in the front of the forearm. It can contribute to pain in the wrist near the thumb. Pain is often felt in the thumb pad and can extend up into the forearm. Cupping the hand can become almost impossible because of intense pain in the wrist and or thumb pad.
The extensor carpi radialis brevis muscle is located in the back of the forearm on the side of the thumb. It contributes to a burning pain in the back of the hand that sometimes extends up to the forearm. Twisting the wrist can cause excruciating pain. It also can cause a weakened unreliable grip.
The extensor carpi radialis longus contributes to pain in the elbow, forearm, back of the hand and first finger. It contributes to tennis elbow and can cause a weak unreliable grip.
The anconeus muscle is located in the forearm contributes to pain in the elbow. Pain is most pronounced when straightening the elbow. It is a prime contributor to tennis elbow and affects golfer's non-dominant elbow.
The brachioradialis is located on the outside of the arm and is a contributor to tennis elbow. It can cause pain on the outside of the elbow, forearm and often descends down into the wrist and thumb. It can contribute to numbness around the thumb as well as a weakened grip.
The supinator muscle is located on the thumb side of the elbow. It can contribute to pain in the elbow, forearm, and back of the hand at the base of the thumb. It can also contribute to numbness and tingling in the thumb side of the hand.
The triceps brachii muscle is found in the back of the upper arm. It can contribute to dull aching pain in the shoulder upper arm, elbow, forearm which occasionally extends into the fingers. The elbow can be hypersensitive and difficult to bend and straighten.
Scalene muscles are a prime contributor to thoracic outlet syndrome as well as neck, shoulder, chest, upper back and arm pain. Muscle twitching, jerking and restlessness similar to restless leg syndrome felt in the neck and shoulder is a classic sign of scalene dysfunction
The pectoralis major contributes to pain in the chest, shoulder, breast and upper back. Pain can also travel down the inner arm, elbow and extend to the hand and last two fingers.