Scientific Terms:

Abduction-moving an appendage’s distal end away from the midsagittal plane.

Flexion- decreasing the angle of a joint.

Extension- increasing the angle of a joint.

Hyperextension- moving a joint beyond its normal range, or beyond the anatomical position.

Plantar flexion- movement of the foot that flexes the foot or toes downward toward the sole.

Dorsiflexion- flexion of the foot in an upward direction.

Qualitative- involving nonnumeric description of quality to analyze human movement.

Quantitative- involving the use of numbers to analyze human movement.

Axis of rotation- imaginary line perpendicular to the plane of rotation and passing through the center of rotation.

Linear- along a line that may be straight or curved with all parts of the body moving in the same direction at the same speed.

Curvilinear- along a curved line.

Sagittal Plane- plane in which forward and backward movements of the body and body segments occur. Sagittal plane movements include flexion, extension, hyperextension, dorsiflexion, and plantar flexion.

Frontal plane- plane in which lateral movements of the body and body segments occur. Frontal plane movements include abduction, adduction, later flexion, elevation, depression, inversion, eversion, and radial and ulnar deviation.

Joint flexibility- a term representing the relative ranges of motion allowed at a joint.

Range of motion- angle through which a joint moves from anatomical position to the extreme limit of segment motion in a particular direction.

Glenohumeral joint- ball and socket joint in which the head of the humerus articulates with the glenoid fossa of the scapula.

Mediolateral axis- imaginary line around which sagittal planes rotations occurs. 

Anatomical reference position- erect standing position with all body parts, including the palms of the hands, facing forward; considered the starting position for body segment movements. 

Anteroposterior axis- imaginary line around which frontal plane rotations occur. 


Agonist- role played by a muscle acting to cause a movement.