The shoulder is a complex joint that consists of a “ball” on one side and a “socket” on the other. Due to this construction, the shoulder is classified as “ball-and-socket” joint. To gain a better perspective on the size of this ball-and-socket joint, think of a golf ball sitting on a tee. On one side you have a really large ball and the other a small socket. The proportions of this large ball and small socket allows for the shoulder joint to have the largest amount of motion of any joint in the body, but there is a price to pay for this amount of motion.