The flexor digitorum profundus muscle is found in the front of the forearm. It can contribute to pain and twitching in the four fingers. It can affect one or any combination of the fingers. It can also cause trigger finger, where a finger will lock in a bent position.
The lumbrical muscles of the hand contribute to pain in the back of the hand and the fingers. Pain in the index finger and/or the little finger are most common. Stiffness in the finger joints mimics arthritis pain. Stiffness and pain when opening and closing the hand is also common.
The opponens pollicis muscle contributes to pain in the thumb and wrist. Pinching and holding objects between the thumb and index finger causes a sharp pain
The palmaris longus muscle contributes to pain in the wrist, the palm of the hand, and will sometimes extend up into the forearm.
The flexor carpi ulnaris muscle is located on the inside (pinky side) of the forearm. It contributes to pain in the wrist, palm of the hand, and the ring and little fingers. Pain is sometimes felt in the elbow.
The flexor carpi radialis muscle is located in the front of the forearm. It contributes to pain in the wrist, bottom of the palm that often extends to the thumb pad and thumb. Twisting the wrist and gripping objects is painful.
The extensor indicis muscle is located in the back of the forearm. It contributes to pain in the back of the wrist, hand, and index finger. The pain will often feel like you have sprained or strained the back of the hand. It can also cause charley horse like cramps in the index finger.
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 ulnaris is found in the back of the forearm toward the side of the little finger. It can contribute to wrist pain. The pain feels like a severe sprain. Twisting the wrist can cause sharp pain. The muscle is also a prime contributor to writers cramp.
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.
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 coracobrachialis muscle connects the shoulder to the upper arm. It can contribute to pain in the shoulder, back of the arm, and occasionally the middle finger. Pain is often felt when attempting to put your hand behind your back and or raising your arm over your head.
The subscapularis muscle is found on the inside of the shoulder blade. It can cause severe pain in the shoulder blade area that can also run down the back of the arm. Pain is also often felt in the wrist, but not the forearm.
The serratus posterior superior muscle is a muscle found in the upper back. It contributes to pain in the shoulder, shoulder blade region, arm, hand and little finger. It can also contribute to pain in the upper chest.
The brachialis muscle connects the upper arm to the lower arm. It contributes to pain in the upper arm, elbow, thumb pad and thumb. It can also cause tingling and / or numbness in the back of the forearm into the thumb. Bending and straightening the elbow is painful.