The study of anatomy relies on standardized imaginary flat surfaces, known as anatomical planes, to describe the location and movement of body structures. These planes allow scientists and medical professionals to map the complex three-dimensional human form into consistent, understandable sections. The body is always viewed in the anatomical position—standing upright, facing forward, with arms at the sides, palms facing forward—before applying these spatial divisions. The frontal plane is one of the three primary planes used to systematically divide the body for analysis.
Defining the Frontal (Coronal) Plane
The frontal plane, also frequently called the coronal plane, is a vertical division that runs from side to side. Its orientation is parallel to the forehead, which is how it receives its secondary name, as coronal refers to the crown of the head. This plane fundamentally divides the body, or any organ, into two distinct sections: the anterior (front) and the posterior (back). Movements that occur within this plane are considered to be side-to-side or lateral motions.
Understanding the Relationship Between All Three Anatomical Planes
The frontal plane gains its context by being one of three principal anatomical planes that are mutually perpendicular to one another. The three planes are the frontal (coronal), the sagittal, and the transverse (axial or horizontal). While the frontal plane creates anterior and posterior sections, the sagittal plane divides the body into left and right halves. The transverse plane, in contrast, is a horizontal division, separating the body into superior (upper) and inferior (lower) portions. These three planes intersect at right angles.
Movements that Occur in the Frontal Plane
Movement is defined as occurring in the frontal plane when it moves parallel to that imaginary front-to-back division. This plane is associated with the anterior-posterior axis, sometimes called the sagittal axis, which is an imaginary line running straight from the front of the body to the back. Any movement rotating around this front-to-back axis will happen within the side-to-side space of the frontal plane.
The primary actions in this plane are abduction and adduction, which involve moving a limb away from and toward the midline of the body, respectively. A familiar example of this is the lateral arm raise, or the outward movement of the legs during a jumping jack. The spine also moves in the frontal plane through lateral flexion, which is the act of bending the torso directly to the side.
Specialized movements at the ankle also occur within this plane, including eversion and inversion, which refer to the sole of the foot turning outward and inward. These side-to-side motions are particularly important in daily life for balance, stability, and avoiding obstacles. Training movements in the frontal plane helps ensure the body is well-rounded and capable of handling movements beyond simple forward and backward actions.