Ball-and-socket joints are a special class of synovial joints that enjoy the highest freedom of motion in the body thanks to their unique structure. The shoulder and hip joints are the only ball-and-socket joints in the human body due to the need for great motion at the end of the body’s limbs and the vast amount of musculature needed to move and support such flexible joints.
Two main components make up a ball-and-socket joint: a bone with a spherical head and a bone with a cup-like socket....