Which synovial joint type allows rotation around a single axis?

• A. Gliding joint
• B. Ball-and-socket joint
• C. Pivot joint
• D. Condyloid joint

Answer: (C)

Rotation around a single axis is a hallmark of pivot joints. In this type of joint, one bone spins about the other along a fixed line, allowing turning motions such as the head rotating at the neck or the forearm rotating at the elbow near the proximal radioulnar joint. This single-axis rotation distinguishes pivot joints from others: gliding joints allow small sliding motions in flat surfaces with little rotation; ball-and-socket joints permit movement around multiple axes and planes; condyloid joints allow motion in two planes but not pure rotation around one axis. So the joint that best fits rotation around a single axis is the pivot joint.