Motion Description Concepts and Terminology – pp 28-40

• Objectives:– Define and provide examples of linear, angular,

& general forms of motion – Identify & describe reference positions, planes,

and axes associated with the human body– Define & appropriately use directional terms &

joint movement terminology

Forms of motion (p 28-30)– Linear - moves from one place to another, or translates

• Rectilinear (straight-line) - ex. path of a dropped ball• Curvilinear (path is curved) - ex.: path of thrown ball

– Rotary, or angular - movement is around a restricted point, or axis, within the system. Ex: all body segmental movements.

– General, or combination - movement is both linear and rotary. Ex: movement of baseball bat during the swing.

Overview of Movement Description• Movement of a system within a frame of reference

• Before determining the nature of a movement, the mechanical system of interest must be defined.

• System may be a part of the body, the entire body, or the body plus an implement, etc.

Standard Reference TerminologyDirectional Terms

• Superior

• Inferior

• Anterior

• Posterior

• Medial

• Lateral

• Proximal

• Distal

• Superficial

• Deep

Joint Movement Terminology

• In anatomical position, all body segments are considered to be positioned at zero degrees.– Sagittal Plane Movements– Frontal Plane Movements– Transverse Plane Movements

• Other Movements

Movement Planes and Axes

• Planes (See Figure 2.3, p 33)– Transverse (across), frontal (front and back sections),

and sagital (left and right sections)

• Axes– mediolateral (side to side), anterio-posterior (front to

back), longitudinal, and diagonal (or oblique)

• Movements– Flexion-extension (mediolateral axis, sagital plane)

» example: squats at the knee and hip

– Abduction-adduction (anterio-post axis, frontal plane)» example: raising arm to side of shoulder

– Rotation (longitudinal axis, transverse plane)» example: turning head to side

Movements in SagitalPlane

MovementsIn Frontal Plane

Movements in Transverse plane

Flexion-extension

Abduction-adduction

Rotation:

Standard Reference TerminologyAnatomical Reference Position

• Erect standing position – all body parts, including the palms of the

hands, facing forward; considered the starting position for body segment movements

Spatial Reference Systems

• Used to standardize the measurements takenCartesian Coordinate system• Movements primarily in a single direction,

or planar, can be analyzed using a two-dimensional Cartesian– X (horizontal) direction– Y (vertical) direction

• 3-dimensional by adding a z-axis