If flexion decreases a joint angle, what is the opposite movement that increases a joint angle?

• A. Extension
• B. Adduction
• C. Elevation
• D. Hyperextension

Answer: (A)

The movement that increases a joint angle is known as extension. When a joint undergoes extension, the two segments that form the joint move away from each other, thus increasing the angle between them. This process is essentially the opposite of flexion, which involves decreasing the angle at the joint as the two segments come closer together.

For example, when standing upright and moving the arms from a bent position at the elbows to a straight position, the elbows are being extended. Extension can occur in many joints throughout the body, such as the knees, hips, and shoulders, making it a fundamental movement pattern.

In contrast, while adduction involves moving a limb towards the midline of the body, it does not primarily relate to increasing joint angles. Elevation refers to moving a body part superiorly, such as shrugging the shoulders, and hyperextension involves extending a joint beyond its usual range of motion. Therefore, extension is the specific movement that accurately describes increasing a joint angle.