Straightening or the act of straightening is called

• A. Flexion
• B. Pronation
• C. Rotation
• D. Extension

Answer: (D)

Straightening a joint increases the angle between the bones, which is called extension. When you straighten the elbow or knee, you’re moving toward a straightened, anatomical position. This contrasts with flexion, which bends the joint and reduces that angle. Pronation involves rotating the forearm to turn the palm downward, while rotation itself refers to turning around a joint’s axis. So the act of straightening fits the term extension, the opposite of bending. In everyday terms, extending the leg or arm returns it toward a straight alignment, whereas flexing would bring it closer to the body.