Which of the following best describes the term "extension"?

The term "extension" in anatomical terms refers to the action of moving a limb or joint away from the center of the body, thereby increasing the angle between body parts. This is a common movement seen in various physical activities and exercises, where straightening out a limb, such as at the elbow or knee, allows for greater reach or distance. For instance, extending the arm upward increases the distance from the shoulder to the hand, illustrating the principle of extension. This distinguishes it from actions like flexion, where the limbs are brought closer together or bent, thereby decreasing the angle between body parts. Understanding this movement is essential in various fields including physical therapy, sports science, and anatomy.