Extension increases the angle between articulating bones, often to restore a body part to its anatomical position after it has been flexed. Hyperextension is continuation of extension beyond the anatomical position. In rotation, a bone moves in a single plane around its longitudinal axis. 5. In circumduction, the distal end of a part of the body moves in a circle. Abduction usually refers to movement of a bone away from the midline of the body.
Adduction usually refers to movement of a bone toward the midline of the body.
E. Special Movements at Diarthroses 1. In addition to the movements listed above, special movements occur at particular joints. F. Details of the Shoulder and Knee Joints 1. There is a structural array of tendons and ligaments that merge with the articular capsule, along with bursae that separate these structures and reduce the friction of relative movement. Because of the low inherent strength of this joint it is suseptable to dislocation type injuries.