Which movement is associated with the sagittal plane?

The sagittal plane divides the body into left and right halves and is primarily associated with movements that occur forward and backward. Flexion and extension are movements that take place in the sagittal plane; flexion decreases the angle between two body parts, while extension increases it. For example, actions such as bending at the elbow or knee (flexion) and straightening the arm or leg (extension) occur in this plane.

In contrast, abduction and adduction, which move limbs away from or towards the midline of the body, occur in the frontal plane, while rotational movements take place in the transverse plane, which divides the body into upper and lower parts. Therefore, the movement associated with the sagittal plane is specifically flexion and extension, making that the correct answer.