Your shoulder is the most movable joint in your body. It allows you to take place and rotate your arm in many positions in front, above, to the side and behind your body. This flexibility also makes your shoulder susceptible to instability and injury.
The shoulder is a ball-and-socket joint. It is made up of three bones: the upper arm bone (humerus), shoulder clade (scapula) and collarbone (clavicle). The bones of the shoulder are held in place by muscles, tendons and ligaments. Tendons are tough cords of tissue that attach the shoulder muscles to bone and assist the muscles in moving the shoulder. Ligaments attach shoulder bones to each other, providing stability. The rotator cuff is a structure composed of tendons that work along with associated muscles to hold the ball at the top of the humerus in the glanoid socket and provide mobility and strength to the shoulder joint.
The shoulder is easily injured because the ball of the upper arm is larger than the shoulder socket that holds it. Although the shoulder is easily injured during sporting activities and manual labor, the primary source of the shoulder problems appears to be the natural age-related degeneration of the surrounding soft tissues such as those found in the rotator cuff. Shoulder pain may be localized or may be felt in areas around the shoulder or down the arm.
Your elbow joint is where three bones in your arm meet: your upper arm bone (humerus) and the two bones in your forearm (radius and ulna). It is a combination hinge and pivot joint. The hinge part of the joint lets the arm bend and straighten; the pivot part lets the lower arm twist and rotate. Elbow injuries can be minor ir serious and may include symptoms such as pain, swelling, numbness, tingling, weakness, or decreased range of motion.