In which plane does flexion and extension occur?

Flexion and extension are movements that decrease or increase the angle between body parts, respectively. These movements primarily occur in the sagittal plane, which divides the body into left and right sections. When you think about common movements such as bending at the elbow or straightening the knee, these actions illustrate flexion and extension taking place within this plane.

The sagittal plane allows for forward and backward movements, which are characteristic of flexion and extension. For example, when performing a bicep curl, the movement of bringing the forearm toward the upper arm is flexion, while the return to the starting position is extension.

In contrast, the frontal plane involves movements such as abduction and adduction, where body parts move away from and towards the midline of the body. The transverse plane relates to rotational movements and divides the body into upper and lower portions, while the horizontal plane is often synonymous with the transverse one, emphasizing horizontal movements rather than the flexion and extension associated with the sagittal plane. Hence, the identification of the sagittal plane as the one where flexion and extension occur is accurate and foundational in understanding human movement and anatomy.