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 flexor digitorum superficialis is located in the front of the forearm. It contributes to pain in the four fingers, the palm, and occasionally the wrist. The muscle is a major contributor to trigger finger.
The flexor pollicis longus muscle is located in the forearm, same side as the thumb. It contributes to pain in the middle joint and tip of the thumb. Pinching motions between the forefinger and thumb can cause intense pain. It can also cause the middle thumb joint to pop and sometimes lock.
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 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 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.
The latissimus dorsi muscle can contribute to pain in the shoulder, upper back, and arm going down into the hand. The muscle can also cause pain in the side of the ribcage and lower abdomen. It is the muscle that most often causes the 'side stitch'.
The subclavius muscle is found just under the collarbone. It contributes to pain in the area around the clavicle (collarbone), shoulder, upper arm, forearm, thumb and fingers. It can also contribute to tingling and numbness in the arm and hand.
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 teres major is a shoulder muscle. It can contribute to pain in the shoulder, upper arm, and forearm. An indication of teres major muscle involvement is pain is felt in the shoulder and upper arm skipping the elbow and reoccurring in the back of the forearm.
The infraspinatus muscle lines the back of the shoulder blade. It is one of the muscles that can contribute to frozen shoulder. The muscle can cause pain in the shoulder, neck, pain down the outside of the arm which descends down into the thumb and hand. Shoulder mobility can be greatly reduced.
The supraspinatus muscle is one of the four rotator cuff muscles. It contributes to pain in the shoulder, outside of the arm and elbow. Pain is a deep aching that often persists during rest.
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 anterior muscle contributes to pain down the side of the ribs, around the shoulder blade, chest, arm, hand, and fingers.
The trapezius muscle is located in the upper back. It can contribute to headaches and pain in the eye, jaw, neck, top of the shoulder and upper back. It can also contribute to tingling in the arm.
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.