Muscles around the shoulder related to shoulder pain.
Trapezius muscle Trapezius muscle is a broad triangular muscle at neck and upper back, one of the largest superficial muscles at the back. It attaches to the base of the skull and extends down to the neck, the upper back until mid-back; laterally it inserts to the shoulder blades. There are three functional regions to the muscle: the Upper, middle, and lower trapezius, and each region has its own function: upper region moves the shoulder blades and support the arms; the middle region retracts the shoulder blades, and the lower region rotates and depresses the shoulder blades. Pain caused from this muscle may be on the top of the shoulder, neck, mid back and/or upper shoulder pain; pain at the back of the shoulder blade which could go down the inside of the arm to the ring and little fingers. Latissimus dorsi Latissimus dorsi is the largest flat muscle at the back. This muscle is involved in adducting the arms, extending the shoulders, and rotating shoulder joints medially. It also play