Which of the following is an example of a hinge joint? A) Knee B) Ankle C) Elbow D) Spine

1. **Definition:** A hinge joint is a type of synovial joint that permits movement primarily in one plane, allowing flexion and extension. It works similarly to a door hinge. 2. **Analysis of Options:** - **A) Knee:** Although the knee largely behaves as a hinge joint, it is often considered a modified hinge joint because it also allows a slight rotational movement. - **B) Ankle:** The ankle is not a pure hinge joint; it functions more as a pivot and multiplanar joint. - **C) Elbow:** The elbow joint is a classic example of a hinge joint, permitting mainly flexion and extension, with very limited additional movement. - **D) Spine:** The spine consists of multiple joints that allow various types of movements (flexion, extension, lateral bending, and rotation) but is not classified as a hinge joint. 3. **Conclusion:** The elbow joint best exemplifies a hinge joint. \[ \boxed{\text{C) Elbow}} \]