In order for a striated muscle to effect movement, the muscle must work in conjunction with the body's hard, jointed framework, called the skeleton. The human body, as do all vertebrates, has an endoskeleton, where the skeleton is contained within the body with the muscles to the outside, as opposed to the arthropod-type exoskeleton, where the skeleton forms the outside of the body with the muscles and organs contained within. The skeleton functions in several important ways: 1) as the structure that the muscles to pull against, 2) as the structure that maintains the body's shape, and 3) as the structure that protects the vital organs. With regard to the third function, the skull and the vertebral column protect the brain and spinal chord, and the rib cage protects the organs of the thoracic cavity.
