1. Planes of Motion and Axes
Biomechanics is the study of human movements through the use of physics. As such, biomechanics has its own language and terminology. The language of biomechanics establishes a common reference system of standard terms. Planes and axes of motion are an important part of this language.

2. Planes of Motion
Plane of Motion: the two dimensional space cut by a moving body or the plane along which movements occur.
There are generally three planes used to describe segmental and body
movements in physical activity. These are:
Sagittal plane
a vertical plane that cuts the body into right and left sides
Frontal plane
vertical plane that cuts the body into anterior (front) and posterior (back) parts
Transverse plane
horizontal plane that cuts the body into superior and inferior parts

3. Anatomical Planes

4. Anatomical Axes
Anatomical Axis: the point about which rotation of a body or of a body segment occurs.
There are three axes of rotation. Each axis is associated with a plane of motion and the
axis is perpendicular to that plane.
Horizontal axis (…think East and West)
passes through the body from side to side
perpendicular to the sagittal plane
Antereoposterior Axis
passes through the body from front to back
perpendicular to the frontal plane
Longitudinal Axis (…think North and South pole)
passes through the body from top to bottom
perpendicular to the transverse plane

5. (e.g. front roll, back roll, cycling, running)
Planes & Movements
Movements in the sagittal plane around a horizontal axis
(e.g. front roll, back roll, cycling, running)
Flexion
flexion at a joint results in a decrease of the angle between the two segments that meet at that joint
Extension
extension at a joint results in an increase of the angle between the two segments that meet at that joint
if the movement occurs beyond the extended position, the action is called hyperextension

6. Examples of Flexion and Extension
shoulder flexion and extension
elbow flexion and extension
wrist flexion and extension
fingers flexion and extension
hip flexion and extension
knee flexion and extension
ankle dorsi flexion and plantar flexion

7. Planes & Movements Movements in a Transverse Plane around a
Longitudinal Axis
(e.g. twist, pirouette)
Rotation
The movement of a bone around its own axis; this is also known as a pivot
E.g. The head, neck and trunk can pivot around the longitudinal axis
Internal Rotation
Rotation towards the midline
e.g. Turning forearm away from body
External Rotation
Rotation away from midline
e.g. turning forearm away from body
Pronation
Rotation of the forearm and hand to the palms down position
Supination
Rotation of the forearm and hand to the palms up position

8. (e.g. cartwheel, jumping jacks, galloping)
Planes & Movements
Movements in the Frontal Plane around an
Antereoposterior Axis
(e.g. cartwheel, jumping jacks, galloping)
Abduction
occurs when a body part is moved away from the midline of the body
e.g. shoulder, hip, fingers
Adduction
occurs when a body part is moved toward the midline of the body
remember “add to your midline”

9. Movements & Planes Inversion
Turning the sole of the foot inward at the ankle
the sole of the foot faces toward the midline
Eversion
turning the sole of the foot outward at the ankle
the sole of the foot faces away from the midline
Elevation
raising a part to a superior position
e.g. raising your shoulders toward your ears; closing your jaw
Depression
lowering a part to an inferior position
e.g. lowering your shoulders to normal or lower than normal position; lowering your jaw to an open position

10. Movements & Planes Protrusion Sticking jaw out (pouting) Retrusion
Bringing jaw back to anatomical position
Lateral bending
bending of the spinal column in the frontal plane to the left or right
e.g. bending side to side at the waist

11. Special Movements Circumduction Opposition Reposition
a combination of abduction, adduction, flexion and extension
this action describes a circle
e.g. moving the shoulder in a circle
e.g. swimming, windmill throw in baseball
Opposition
Bringing thumb towards fingers
Reposition
Returning thumb back to anatomical position