Which joint allows movement around one axis in the transverse plane, such as the radioulnar joint?

Which joint allows movement around one axis in the transverse plane, such as the radioulnar joint?

• A. Pivot joint
• B. Hinge joint
• C. Ball-and-socket
• D. Saddle joint

Answer: (A)

Movement around a single axis in the transverse plane describes rotation, which is a uniaxial motion. The radioulnar joints rotate the radius around the ulna to allow pronation and supination, a classic example of rotation at a pivot joint. Pivot joints are built to allow this one-axis rotation, while other joints either move mainly in a different plane (like hinge joints, which flex and extend mainly in the sagittal plane), or permit multiple axes of movement (ball-and-socket and saddle joints). So the pivot joint best fits the idea of rotational movement around one axis seen in the radioulnar joints.

Movement around a single axis in the transverse plane describes rotation, which is a uniaxial motion. The radioulnar joints rotate the radius around the ulna to allow pronation and supination, a classic example of rotation at a pivot joint. Pivot joints are built to allow this one-axis rotation, while other joints either move mainly in a different plane (like hinge joints, which flex and extend mainly in the sagittal plane), or permit multiple axes of movement (ball-and-socket and saddle joints). So the pivot joint best fits the idea of rotational movement around one axis seen in the radioulnar joints.