Anatomical planes are imaginary flat surfaces used to divide the human body into sections for study and description. These planes provide a universal system of reference necessary for clear communication among medical professionals and anatomists. By establishing a common language for describing the location of structures, injuries, or surgical procedures, they ensure accuracy in clinical and educational settings.
Establishing the Reference Point
The accurate application of these dividing planes depends on a standardized starting posture called the “anatomical position.” This fixed reference point is defined by the body standing upright, facing forward, with the feet slightly apart and parallel. The arms are held straight at the sides, and the palms of the hands are turned to face forward.
This specific pose is essential because it anchors all subsequent directional terms and planes. Without this standard position, terms like “above” or “below” would change depending on whether a person was sitting or lying down. The anatomical position establishes a consistent coordinate system, making descriptions of any structure’s location precise and unambiguous.
Defining the Three Core Planes
The three primary anatomical planes intersect at right angles to one another, slicing the body in three distinct ways.
The sagittal plane is a vertical division that runs from front to back, separating the body into right and left portions. The midsagittal plane passes exactly through the body’s midline, creating two equal halves. Any other plane parallel to this midline division is termed a parasagittal plane, resulting in unequal right and left sections.
The coronal plane, also known as the frontal plane, is another vertical division, but it runs perpendicular to the sagittal plane. This cut divides the body into an anterior (front) section and a posterior (back) section.
The third division is the transverse plane, often called the horizontal or axial plane. This plane is positioned parallel to the ground and is perpendicular to both the sagittal and coronal planes. A transverse cut divides the body into a superior (upper) section and an inferior (lower) section.
How Planes Aid Medical Imaging
The concept of anatomical planes is directly applied in modern diagnostic medicine, particularly in advanced imaging techniques like Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). These machines use the planes to generate detailed cross-sectional pictures, or “slices,” of the body’s interior. A CT scanner, for instance, often primarily acquires images in the transverse plane, producing axial slices.
Imaging software then uses the data from these slices to reconstruct views in the other two planes. A doctor can review a “coronal view,” which displays the body as if it were cut into front and back sections, or a “sagittal view,” showing a profile perspective. This ability to visualize internal organs, soft tissues, and bone from three distinct orientations is crucial for diagnosing tumors, internal injuries, and structural abnormalities.