Female Anatomical Planes & Axes Explained: A Visual Guide for Physiotherapy

Anatomical planes are imaginary flat surfaces that divide the body, and axes are imaginary lines through a joint around which a bone rotates. The three cardinal planes are sagittal, frontal and transverse. In a simplified single-plane model, each plane has one perpendicular axis: mediolateral, anteroposterior or longitudinal. Together they give clinicians a shared language for describing movement.

This article is educational. The planes, axes and bodies shown here are simplified, and nothing on this page is personal treatment advice.

Anatomical planes are imaginary flat surfaces that divide the body, and axes are imaginary lines through a joint around which a bone rotates. The three cardinal planes are sagittal, frontal and transverse. In a simplified single-plane model, each plane has one perpendicular axis: mediolateral, anteroposterior or longitudinal. Together they give clinicians a shared language for describing movement.

This article is educational. The planes, axes and bodies shown here are simplified, and nothing on this page is personal treatment advice.

What you will learn

• Describe the anatomical position and use directional terms correctly.
• Explain the difference between a plane and an axis.
• Name the three cardinal planes, what each divides and the movements that typically occur in it.
• Match each plane with its perpendicular axis, including alternative names.
• Apply the ideas to the shoulder, hip, knee, elbow, forearm, ankle, foot and trunk.
• Identify the plane and axis of a movement you observe, and know the limits of that simplification.

Anatomical position and direction

Anatomical position is the standard reference for describing the body. The person stands upright, facing forward, with the feet together or slightly apart, the arms by the sides and the palms facing forward. Everything is described as if the body were in that position, which means descriptions stay consistent whoever is looking and however the person is actually standing or moving. Real movement does not have to start from anatomical position; the position is a map reference, not a rule.

Planes and axes apply equally to every body. The figure used in this article is a neutral, schematic adult female model, and it is a simplification, not a measurement of any individual.

Learn these direction words first, because plane and axis descriptions depend on them:

• Superior and inferior: towards the head and towards the feet.
• Anterior and posterior: towards the front and towards the back.
• Medial and lateral: towards the midline and away from it.
• Proximal and distal: nearer to or further from the trunk, used for limbs.
• Left and right always mean the patient's left and right, not the observer's.

Plane versus axis

A plane is an imaginary two-dimensional surface. It is used to describe where a movement happens, in the way a flat sheet might slice through the body.

An axis is an imaginary line. It is used to describe what a movement rotates around, in the way a door turns about its hinge.

In a simplified model where a bone swings within one plane, the axis of rotation is perpendicular to that plane. A door swings across the floor, a flat surface, around a vertical hinge, which is a line at right angles to it. Joints work in the same way: the movement sweeps through a plane, and the pivot line passes through the joint at right angles to it.

The sagittal plane

The sagittal plane runs from front to back and divides the body into left and right portions. Many planes can be sagittal, because any vertical plane parallel to this direction counts. Two terms matter:

• The midsagittal (or median) plane passes through the middle of the body. It is the only sagittal plane that divides the body into equal left and right halves.
• Parasagittal planes lie parallel to the midsagittal plane, to either side of it.

Movements in the sagittal plane are forward and backward movements. The typical examples are flexion and extension: bending and straightening the elbow, flexing the spine forward, flexing the hip or the shoulder, and dorsiflexion and plantarflexion of the ankle.

The perpendicular axis is the mediolateral axis, running from side to side. You will also see it called the frontal axis or the transverse axis, which is a common source of confusion because those names are used for other things too. The mediolateral name describes exactly where the line runs, so this article uses it.

The frontal plane

The frontal plane, also called the coronal plane, runs from side to side and divides the body into anterior and posterior portions, front and back. Frontal and coronal are two names for the same plane. Like sagittal planes, frontal planes do not have to divide the body into equal parts; a frontal plane can pass through the body at any depth.

Movements in the frontal plane are side-to-side movements. Typical examples are:

• abduction and adduction of the shoulder and hip, which move the limb away from and back towards the midline;
• lateral flexion of the spine, bending the trunk or neck sideways;
• radial and ulnar deviation of the wrist;
• elevation and depression of the shoulder girdle.

The perpendicular axis is the anteroposterior axis, running from front to back. It is sometimes called the sagittal axis, because it lies in the direction of the sagittal plane.

The transverse plane

The transverse plane, also called the horizontal plane, runs parallel to the floor when the body is upright and divides it into superior and inferior portions, upper and lower. Transverse and horizontal are common synonyms, and some texts use transversal. As with the other planes, it does not need to split the body into equal halves.

Movements in the transverse plane are twisting or rotational movements. Typical examples are:

• rotation of the spine, head and neck;
• internal and external rotation of the shoulder and hip;
• pronation and supination of the forearm;
• horizontal abduction and adduction of the shoulder, with the arm held at shoulder height.

The perpendicular axis is the longitudinal axis, which is vertical when the body is in the upright reference position. A limb has its own longitudinal axis too, and when the limb is raised, its axis is not vertical in the room. Always say which coordinate system you are using.

The three axes and their other names

Every axis has more than one name in the literature, which is why students lose marks on terminology. The consistent pairing used throughout this article is:

• Mediolateral axis: runs left to right. Also called the frontal axis or transverse axis. It is perpendicular to the sagittal plane.
• Anteroposterior axis: runs front to back. Also called the sagittal axis. It is perpendicular to the frontal plane.
• Longitudinal axis: runs top to bottom. Also called the vertical or superoinferior axis. It is perpendicular to the transverse plane.

If an exam question uses a different label, work out the direction of the line, then decide which name it is using.

Plane, axis and movement at a glance

• Sagittal plane: divides the body into left and right portions. Axis: mediolateral. Typical movements: flexion and extension.
• Frontal (coronal) plane: divides the body into anterior and posterior portions. Axis: anteroposterior. Typical movements: abduction, adduction and lateral flexion.
• Transverse (horizontal) plane: divides the body into superior and inferior portions. Axis: longitudinal. Typical movements: axial rotation, and horizontal abduction and adduction.

Joint examples

Shoulder and hip

The shoulder and hip are ball-and-socket joints. In the simplified model they have three rotational degrees of freedom, so movement can occur about all three axes. Shoulder flexion and extension are sagittal movements about a mediolateral axis. Shoulder abduction and adduction are frontal movements about an anteroposterior axis. Internal and external rotation are transverse movements about the longitudinal axis of the humerus. The hip works in the same way, with flexion and extension, abduction and adduction, and rotation.

Knee

The knee is best described as a modified hinge joint. Its predominant motion is flexion and extension in the sagittal plane about a mediolateral axis. It also allows real axial rotation, particularly when the knee is flexed. That rotation is part of normal knee function, and it is different from passive laxity or from motion that is coupled with another movement. So the knee is mainly sagittal, but it is not only sagittal.

Elbow and forearm

Elbow flexion and extension are sagittal movements about a mediolateral axis. Pronation and supination of the forearm are separate. They happen at the radioulnar joints, not at the elbow hinge, and they are rotations about the long axis of the forearm. Keep the two apart: bending the elbow and turning the palm are different movements at different joints.

Ankle and foot

Dorsiflexion and plantarflexion at the ankle are predominantly sagittal movements about a mediolateral axis.

Inversion and eversion are usually listed as frontal-plane movements, but this is a simplification. The foot has several joints with oblique axes, so these movements combine components in more than one plane. They should not be confused with pronation and supination of the foot, which describe composite movements.

Trunk

Spinal flexion and extension are sagittal. Lateral flexion is frontal. Spinal rotation is transverse. The range available differs by region, and most everyday trunk movements combine all three.

Circumduction and multiplanar movement

Circumduction, such as drawing a circle with the arm, is not a fourth plane and not a separate rotation. It is a sequence of flexion, abduction, extension and adduction performed in order.

More generally, real movement is multiplanar. Walking, running, squatting and sport involve several joints, each moving in more than one plane at once, along with small translations and axes that shift during the movement. One plane may dominate a particular joint action, but the whole task rarely stays inside it.

How physiotherapists use planes and axes

• Observation. A view approximately perpendicular to the plane of movement helps isolate that movement. A side view shows sagittal movements well; a front or back view shows frontal movements. Complex movements often need more than one view.
• Describing movement. Planes and axes let a clinician describe the same movement the same way as a colleague, in a report, or in a handover.
• Gait and posture. Clinicians commonly look at the sagittal plane for movements such as knee flexion, the frontal plane for pelvic and trunk lean, and the transverse plane for rotation.
• Exercise analysis. Describing an exercise by plane shows what it does and what it leaves out, which helps when planning a varied programme.
• Documentation. Consistent terms make notes clear, for example measuring and recording shoulder abduction rather than describing the arm going out to the side.

These are general uses of the vocabulary, not advice for any person. A physiotherapist decides what applies to an individual after assessment.

How to identify the plane and axis of a movement

Use four steps:

1. Name the joint and the starting position.
2. Describe what the moving segment does, such as swinging forwards, sideways or twisting.
3. Decide which plane that movement sweeps through.
4. Find the axis, the line through the joint at right angles to that plane.

Worked example: raising the arm out to the side.

• Joint: the shoulder (glenohumeral joint), starting with the arm by the side in anatomical position.
• Movement: the arm lifts sideways, away from the midline.
• Plane: the frontal plane, since the arm moves side to side.
• Axis: the anteroposterior axis, running front to back through the shoulder.
• Name: abduction.
• Limits: the shoulder blade and collarbone also move during a full lift, and a real lift is rarely in a single perfect plane, so this is a simplified description.

Common mistakes and exam traps

• Saying that all sagittal planes give equal halves. Only the midsagittal plane does.
• Treating frontal and coronal as different planes. They are the same.
• Mixing up the plane with the axis. The plane is the surface; the axis is the line perpendicular to it.
• Using "transverse axis" without checking what it means. Some texts use it for the mediolateral axis, and the transverse plane is a different thing.
• Treating the knee as a pure hinge, or saying it has no rotation.
• Calling circumduction a fourth plane.
• Confusing elbow flexion with forearm pronation and supination.
• Assuming every movement stays in one plane.

A memory aid

Think of three directions: side to side, front to back, and top to bottom. Every plane contains two of them, and its axis is the one it does not contain. The sagittal plane contains front-to-back and top-to-bottom, so its axis runs side to side. The frontal plane contains side-to-side and top-to-bottom, so its axis runs front to back. The transverse plane contains side-to-side and front-to-back, so its axis runs top to bottom. If you can say that for each plane, you have it.

Key takeaways

• A plane is a surface; an axis is the line perpendicular to it.
• Sagittal: left and right, mediolateral axis, flexion and extension.
• Frontal (coronal): anterior and posterior, anteroposterior axis, abduction, adduction and lateral flexion.
• Transverse (horizontal): superior and inferior, longitudinal axis, rotation.
• Only the midsagittal plane gives equal halves.
• The knee is a modified hinge with real axial rotation, and circumduction is a sequence, not a fourth plane.
• Real movement is multiplanar, and every diagram here is a simplification.

Glossary

• Abduction / adduction: movement away from and towards the midline of the body.
• Anatomical position: the standard upright reference position used to describe the body.
• Arthrokinematics: the small gliding, rolling and spinning movements between joint surfaces.
• Axis of rotation: an imaginary line through a joint around which a segment rotates.
• Circumduction: a circular movement made by combining flexion, abduction, extension and adduction in sequence.
• Osteokinematics: the movement of bones as seen from outside the joint, described in planes and axes.
• Plane: an imaginary flat surface used to describe where a movement occurs.

References

Verify the current edition of each reference before relying on it.

• Standring S, editor. Gray's Anatomy: The Anatomical Basis of Clinical Practice. Elsevier.
• Neumann DA. Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation. Elsevier.
• Kapandji AI. The Physiology of the Joints. Churchill Livingstone.
• Norkin CC, White DJ. Measurement of Joint Motion: A Guide to Goniometry. F.A. Davis.
• Wu G, et al. ISB recommendation on definitions of joint coordinate system of various joints for the reporting of human joint motion, Part I: ankle, hip, and spine. Journal of Biomechanics. 2002;35(4):543-548.
• Wu G, et al. ISB recommendation on definitions of joint coordinate systems of various joints for the reporting of human joint motion, Part II: shoulder, elbow, wrist and hand. Journal of Biomechanics. 2005;38(5):981-992.

This article is for education. It is not medical advice and does not replace assessment by a qualified physiotherapist. If you are in pain or have a movement problem, book an assessment or contact the studio.