The document discusses different types of joints in the skeletal system. It describes three main classifications of joints: fibrous joints that connect bones using connective tissues, cartilaginous joints that connect bones using cartilage, and synovial joints that are the most complex and allow for the most movement. Within these classifications are various sub-types of joints, including ball-and-socket, hinge, pivot, and others. Examples are provided of specific joints like the shoulder, elbow, and hip. The document also covers joint movements, life-span changes to joints, and common joint disorders.