Tendons are flexible, but tough, connective tissues that attach muscles to bones. They play a crucial role in the movement of the body, as they transmit the force generated by the contracting muscle to the bone to produce movement. Tendons are made of densely packed collagen fibers, which provide excellent tensile strength and help the tendon withstand the high forces generated during movement. The structure of tendons varies depending on their location, and they are also supplied with blood vessels and nerves to help maintain their function.