A joint (also called an articulation) is formed at the junction where two bones meet. Joints are integral to the body's strength and mobility. Joints are classified into different types depending on their function and structure. Different types of materials can connect bones, including fluid, fibrous connective tissue, and cartilage. Some joints move freely, some move slightly, and others are completely immobile. The degree of mobility is determined by the shapes of the ends of the bones. Ligaments connect bones, and tendons link muscles and bones to provide additional strength and facilitate proper mobility. The body uses lever systems, which allow the muscles, bones, and joints to work together to create movement.

At A Glance

  • There are three common types of joints that are classified based on their structure: fibrous joints, cartilaginous joints, and synovial joints.
  • Synovial joints are highly movable joints with a complex structure that protects bones from damage while allowing many types of movements.
  • Lever systems used during movements allow muscles, bones, and the joints between bones to work together to generate motions in a way that maximizes either speed or force.
  • Tendons and ligaments are both examples of fibrous connective tissue containing collagen; tendons attach muscle to bone (or other organs), and ligaments connect bone to bone.