The musculoskeletal system is comprised of bones, muscles, tendons, ligaments, and other components of joints. The hard outer part of the bone is made up of proteins and a substance called hydroxyapatite. Hydroxyapatite stores most of the body's calcium and is primarily responsible for the strength of bones. Marrow is located in the center of each bone. Blood cells are manufactured within the marrow.
Bones come together to form joints. Joints are responsible for the degree and direction of motion.
Muscles are comprised of bundles of fibers and are responsible for posture and movement. Skeletal muscles are attached to bones and are arranged in opposing groups surrounding the joints.
Tendons and ligaments are two types of tissue. Both of these tissues strengthen and support joints, facilitating movement.
View sub-topics at right to learn more about some specific bone, joint, and muscle disorders and some of their common causes.