Understanding the three planes and axes of the human body

The concepts of planes and axes in the human body are fundamental tools used to describe movement, anatomy, and positioning. However, they often leave students feeling confused. Over the years, I have noticed that diagrams showing a person sliced into sections by imaginary squares or pierced by lines rarely clarify the topic (see for yourself below!). To make things clearer, I will explain the planes and axes in a straightforward way and offer a simple prop-based method to help you visualise and understand what they represent.
The human body can be divided into three planes and three axes, which work together to describe how the body moves. These concepts are widely used in fields like anatomy, sports science, physiotherapy, and fitness.

What are the planes of the body?
Planes are like invisible sheets that “slice” through the body in different directions. They help us describe where movements occur or how body parts are positioned. There are three primary planes:

1. Sagittal plane: This plane divides the body into left and right halves. Movements in the sagittal plane are forward and backward motions, such as walking, running, performing a bicep curl, or nodding your head.
2. Frontal (coronal) plane: The frontal plane divides the body into front (anterior) and back (posterior) halves. Movements in this plane involve side-to-side motions, such as raising your arms out to the side, tilting your head towards one shoulder, jumping jacks or side lunges.
3. Transverse (horizontal) plane: The transverse plane divides the body into top (superior) and bottom (inferior) halves. Movements in this plane involve rotation, such as twisting your torso, swinging a golf club, or turning your head.

What are the axes of the body?
Axes are imaginary lines around which the body or a body part rotates during movement. Every movement occurs in a plane and rotates around an axis. Axes act like pivot points or hinges for motion, and they are closely connected to the planes of the body. There are three primary axes:

1. Longitudinal axis: This axis runs vertically from head to toe. Movements around the longitudinal axis are rotational, such as spinning on ice skates or turning your head side to side.
2. Sagittal (anterior-posterior) axis: This axis runs from front to back. Movements around the sagittal axis are side-to-side motions, such as cartwheels or raising your arms out to the sides.
3. Transverse (medial-lateral) axis: This axis runs from side to side. Movements around the transverse axis are forward and backward motions, such as somersaults, bending your knees, or flexing and extending your elbows.

How do planes and axes work together?
Movements in the human body can always be described as occurring in a plane (the flat surface where the motion takes place) and around an axis (the imaginary line about which the movement rotates). This relationship between planes and axes is fundamental to understanding how the body moves and how different types of motion are classified. To better grasp this concept, let us examine three major types of movement – flexion and extension, abduction and adduction, and rotation – and how they work within specific planes and axes.

Flexion and extension are movements that involve decreasing or increasing the angle between two body parts. These motions occur in the sagittal plane, and they rotate around the transverse axis, which runs horizontally from side to side. For example, bending your elbow to bring your hand toward your shoulder is an example of flexion, while straightening your arm to return to its original position is extension.

Flexion and extension are movements that involve decreasing or increasing the angle between two body parts. These motions occur in the sagittal plane, and they rotate around the transverse axis, which runs horizontally from side to side. For example, bending your elbow to bring your hand toward your shoulder is an example of flexion, while straightening your arm to return to its original position is extension.

Abduction and adduction refer to movements that take a body part away from or toward the midline of the body. These motions occur in the frontal plane, and they rotate around the sagittal axis, which runs horizontally from front to back. An example of abduction is raising your arms out to the side, away from the body, during a dumbbell lateral raise. Adduction is the movement that brings the limb back toward the midline, such as lowering your arms to your sides after a lateral raise.

Rotation is a twisting or turning motion that occurs around a central axis. These movements happen in the transverse plane, and they rotate around the longitudinal axis, which runs vertically from head to toe. An example of rotation is turning your head to look over your shoulder, which involves rotating the cervical spine.

Why are planes and axes important?
Understanding planes and axes is important for several key reasons. Firstly, they are essential for movement analysis, helping professionals such as physiotherapists, fitness professionals, and athletes to assess and improve how the body moves. For instance, identifying which axis is involved in a faulty movement allows for targeted corrections to improve performance or address imbalances. Secondly, they are fundamental in exercise design. Trainers use knowledge of planes and axes to create balanced workouts that incorporate movements in all three planes, ensuring that the body develops strength, mobility, and functionality in a balanced way. Finally, understanding how movements occur around axes is a key factor in injury prevention. Correct alignment and technique during physical activities can minimise the risk of strain or injury, making this knowledge invaluable for both professionals and individuals.

How can you learn and remember these concepts?
There are several effective strategies to help you learn and remember the planes and axes of the body. A useful first step is to visualise the planes by imagining slicing the body with sheets of glass in different directions. The sagittal plane divides the body into left and right halves, the frontal plane divides the body into front and back halves, and the transverse plane divides the body into top and bottom halves. Visualising these divisions can make the concept more tangible.

Relating planes to everyday movements can further reinforce your understanding. For example, walking or running occurs in the sagittal plane, waving your arms to the side happens in the frontal plane, and twisting your torso to look behind you involves the transverse plane. By associating planes with familiar actions, it becomes easier to remember how movements are classified.

Practising with specific exercises is another effective method. Exercises that emphasise each plane can solidify your understanding through physical experience. Lunges, running, and bicep curls are excellent examples of sagittal plane movements. Side lunges, lateral raises, and side shuffles focus on the frontal plane, while Russian twists, torso rotations, and swinging a bat engage the transverse plane.

Finally, using mnemonics can help commit these planes to memory. Simple phrases such as “sagittal splits left and right,” “frontal faces forward,” and “transverse twists” can act as quick reminders of how each plane divides the body and how movements occur within them.

Blog post by

Dave Lee

Dave Lee

Dave Lee is the co-founder of Amac, he continues to write and produce all our courses and you might even find him teaching you.

View Profile