There are three cardinal planes of the human body, and most bodily motions are described as taking place in one of these planes. It is crucial to learn the planes, and the axes that correspond to each of them, to understand the science of movement of the human body. This is extremely important to doctors, nurses and physical therapists who are helping patients recover from injuries, illnesses or other problems that can lead to functional impairment.
Place the body in the anatomical position. This means that the head and feet should be facing forward. The hands should be down at the sides, with the palms facing forward. All cardinal planes are evaluated in terms of anatomical position, so even if this is not a functional position of the joint, it is how the planes will be labelled.
Hold a piece of cardboard in front of the body so the edge of the cardboard is vertical and the line it creates is cutting the body into a right and left half. This is the sagittal plane of the body. Some books will refer to a midsagittal plane as well. The only difference between the midsagittal and the sagittal plane is that the midsagittal goes directly through the middle of the body, whereas the sagittal plane can cut through the body, but perhaps not be exactly in half. The corresponding axis for the sagittal plane is the medial-lateral axis. This means that any joint that moves in the sagittal plane rotates around the medial-lateral axis.
Keep the piece of cardboard vertical and walk to the side of the standing body. If the plane were to cut the body in half through the side, making a front and back half of the body, the plane would be referred to as the frontal or coronal plane. The corresponding axis for the frontal plane is the anterior-posterior axis. This means that the movement would follow the frontal plane and rotate about the anterior-posterior axis.
Turn the cardboard so that it is horizontal and place it in front of the body. This plane is referred to as the transverse plane. It cuts the body in a horizontal direction at any level from head to feet. The corresponding axis for the transverse plane is the vertical axis.
Memorise each plane and the axis that is associated with it. Memorising these in pairs will make diagnostics and treatment much easier.
Be aware that the frontal plane can also be called the coronal plane, and that the two terms are used interchangeably.