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.
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 biceps brachii muscle is found in the front of the upper arm. It contributes to pain in the shoulder, upper arm and elbow. Straightening the arm when the palm is facing up can be painful and difficult.
The deltoid is the muscle that covers the tip of the shoulder. It contributes to pain in the shoulder and upper arm. One indication of problems with the deltoid muscle is pain is most intense during activity and subsides when resting the shoulder and arm.
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 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 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 teres minor connects the shoulder blade to the upper arm and is one of the rotator cuff muscles.