What Bones And Joints Do
Bone is as strong as steel yet as light as aluminium. It may appear rigid but it is constantly remodelling and reforming itself. The protein in bone is supple collagen, the same as in nails The skeleton, held together by tough ligaments, provides a superstructure for muscles and tendon attachments and articulates by means of a variety of different types of joints. Inside each joint is a lubricating synovial fluid. A pet has over 500 individual muscles. Muscles and their associated tendons make up the bulk of a pet's body and account for about half its weight. Some attach directly to bones. Others taper into elastic tendons for attachment to the skeleton. Ligaments attach one bone to another. For example, the cruciate ligaments in the knee, hold the long bones of the leg in close proximity. Tendon and ligament fibres pass through the surface of bone (periosteum) and are embedded in bone itself. This is why, if they tear off bones, repair is difficult. Tendons tear but because of the retraction caused by their natural elasticity, do not repair well.