Which of the following describes extension of a joint?

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

Answer: (B)

Extension is the movement that increases the angle between two bones at a joint, effectively straightening a limb. It moves from a bent position toward or past the neutral anatomical position. For example, straightening the elbow after it has been bent or straightening the knee from a flexed position demonstrates extension. In contrast, flexion decreases that angle by bending the limb. Abduction moves a limb away from the body's midline, and rotation refers to turning a body part around its long axis.