What is the term for a joint that is fixed and does not move?

• A. Immovable joint
• B. Movable joint
• C. Ball and socket joint
• D. Hinge joint

Answer: (A)

Joints are classified by how much they move. When a joint is fixed and doesn’t move, it’s called an immovable joint, also known as a synarthrosis. These joints are held tightly together by dense connective tissue or by bone fusion, so there is no appreciable motion, which helps protect structures like the brain. A familiar example is the sutures between skull bones. In contrast, movable joints allow motion, such as ball-and-socket joints that move in many directions (shoulder, hip) or hinge joints that bend in one plane (elbow, knee). So the term that best fits a joint that stays still is immovable joint.