In the sagittal plane, bending of joints decreases the relative angle.

• A. Extension
• B. Dorsiflexion
• C. Plantar flexion
• D. Flexion

Answer: (D)

In the sagittal plane, flexion is bending a joint so that the angle between the two bones decreases. This is exactly what happens when you bring your hand toward your shoulder at the elbow or bend your knee—the bones move closer together, reducing the joint angle.

Extension is the opposite action: it straightens the joint and increases that angle. Dorsiflexion and plantar flexion are specific ankle movements in the sagittal plane—dorsiflexion brings the foot upward toward the shin (a bending motion at the ankle), while plantar flexion points the toes downward, increasing the angle at the ankle. Since the statement describes a bending that reduces the angle, the term that fits this description is flexion.