Definitions and Terms

Anatomy Action Terms

Flexion a bending movement around a joint in a limb (as the knee or elbow) that decreases the angle between the bones of the limb at the joint

Extension: an unbending movement around a joint in a limb (as the knee or elbow) that increases the angle between the bones of the limb at the joint

Abductto draw away (as a limb) from a position near or parallel to the median axis of the body

Adductto draw (as a limb) toward or past the median the axis of the body

Rotationthe action or process of rotating on or as if on an axis or center; specifically: the turning of a body part about its long axis as if on a pivot

Circumduction: movement of a limb or extremity so that the distal end describes a circle while the proximal end remains fixed 

Protract: to extend forward or outward

Retract: to draw back or in 

All definitions for anatomy action terms from the Merriam-Webster's Medical Dictionary. Merriam-Webster, Inc. 15 Dec. 2011.