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.

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

Anatomical Planes

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

(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

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

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

(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”

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

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

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