The canine skeletal system is a marvel of bones, cartilage, and ligaments that provide the body with a framework to erect on four strong legs, protect internal organs, and provide a full range of motion. The muscles furnish the power to propel the dog into action, but without healthy bones, joints, and connective tissue, the muscles cannot do their job.
Joints — the skeletal hinges — give the skeleton flexibility for walking, trotting, running, jumping, climbing, and moving the head and neck to increase the field of vision. The dog's body has three types of joints: ball and socket such as the hip and shoulder joints; hinged joints such as the knees and elbows; and gliding or plane joints such as the wrists and ankles. The joints are lubricated for smooth action by synovial fluid and are stabilized by tendons and ligaments. When the joints are damaged by injury or disease, arthritis (joint inflammation) can occur.