The planes of the body are three imaginary flat surfaces used to divide the human body into sections. These three planes, called the sagittal, coronal (frontal), and transverse, serve as a universal reference system in anatomy, medicine, and exercise science. Every description of how the body moves or where a structure is located relies on these planes, and once you understand them, anatomical language becomes far more intuitive.
All three planes are defined relative to what’s called the standard anatomical position: a person standing upright, facing forward, arms at the sides, palms facing forward. This starting point ensures that everyone, from surgeons to personal trainers, is speaking the same spatial language.
The Sagittal Plane
The sagittal plane is a vertical plane that runs from the front of the body to the back, dividing it into left and right sections. Picture a pane of glass slicing straight through you from your nose to the back of your head and continuing down through the rest of your body.
There are two important variations. The midsagittal plane (also called the median plane) cuts through the exact center line, splitting the body into equal left and right halves. A parasagittal plane is any vertical front-to-back cut that’s off-center, creating unequal left and right portions. It doesn’t matter which side ends up larger; if the halves aren’t equal, it’s parasagittal.
Movements in the sagittal plane are forward and backward motions. Bending your elbow to lift a dumbbell during a bicep curl is flexion, and straightening it back out is extension. Walking, running, squats, lunges, and deadlifts all happen primarily in the sagittal plane. Even smaller movements like pointing your toes downward (plantar flexion) or pulling them up toward your shin (dorsiflexion) fall into this category. The axis of rotation for these movements runs horizontally from side to side, which is why bending forward and backward naturally pivots around that left-to-right line.
The Coronal (Frontal) Plane
The coronal plane, also called the frontal plane, is another vertical plane, but it runs from side to side rather than front to back. It divides the body into a front (anterior) portion and a back (posterior) portion. Think of it as a sheet of glass passing through you from one shoulder to the other, separating everything in front of that line from everything behind it.
Movements in the coronal plane are lateral, meaning side-to-side. Lifting your leg out to the side (abduction) or bringing it back toward your midline (adduction) are classic examples. Raising your shoulder blades upward (elevation) and pulling them downward (depression) also occur in this plane. At the ankle, turning the sole of your foot inward is inversion, and turning it outward is eversion.
Exercises that target the coronal plane include jumping jacks, side lunges, lateral shuffles, side bends, and lateral arm raises. The axis of rotation for these movements runs from front to back through the body, perpendicular to the plane itself.
The Transverse (Axial) Plane
The transverse plane is the only horizontal plane. It runs parallel to the ground and divides the body into an upper (superior) portion and a lower (inferior) portion. You can place a transverse plane at any height, like an imaginary slice through the waist, chest, or neck.
All rotational and twisting movements happen in this plane. Turning your head left or right is rotation in the transverse plane. So is swinging a baseball bat, throwing a punch with torso rotation, or doing a seated twist. Horizontal abduction and adduction also occur here: if your arm is raised to 90 degrees in front of you and you swing it out to the side, that’s horizontal abduction. Bringing it back across your body is horizontal adduction, which is exactly what happens during a chest fly exercise.
The axis of rotation for transverse plane movements runs vertically from bottom to top, like a pole through the crown of your head down to the ground. Your body rotates around this vertical line.
Oblique Planes
Beyond the three cardinal planes, oblique planes exist at any angle between horizontal and vertical. These don’t follow the neat left-right, front-back, or top-bottom divisions. While they’re less commonly discussed in basic anatomy, oblique planes become relevant in medical imaging, where a radiologist may need to view a structure from an angled perspective that doesn’t line up with any of the standard three planes.
How These Planes Are Used in Medical Imaging
One of the most practical applications of body planes is in diagnostic imaging. CT scans, MRIs, ultrasounds, and PET scans all produce images by slicing through the body along specific planes. A transverse (axial) CT scan of the abdomen, for example, shows a horizontal cross-section as though you were looking down at the body from above. Sagittal and coronal views give front-to-back and side-to-side perspectives, respectively.
By placing a patient in standard anatomical position, a radiologist builds a three-dimensional coordinate system around the body. Each plane then becomes a tool for pinpointing the exact location of a tumor, fracture, or organ abnormality. Individual organs can also be divided by these same planes to identify smaller structures within them. When you receive imaging results that reference “axial” or “coronal” views, those terms are describing which plane the image was captured in.
Why Planes and Axes Work Together
Each plane has a corresponding axis of rotation that runs perpendicular to it. This pairing is what makes movement analysis precise. The sagittal plane pairs with a side-to-side (frontal) axis, so flexion and extension rotate around that horizontal line. The coronal plane pairs with a front-to-back (sagittal) axis, so lateral movements like abduction pivot around it. The transverse plane pairs with the vertical axis, so all rotational movements spin around that up-and-down line.
In practice, very few real-world movements happen purely in one plane. A tennis serve involves sagittal plane shoulder flexion, transverse plane rotation of the trunk, and coronal plane lateral movement all at once. But isolating movements by plane is how clinicians assess joint function, how physical therapists design rehabilitation programs, and how trainers build workouts that target all three dimensions of movement rather than just one.