What is the primary characteristic of rotation in anatomical terms?

The primary characteristic of rotation in anatomical terms is that it involves a pivot or revolution around a single long axis. This movement can be observed in various joints of the body, such as the shoulder and hip, where a limb or part rotates around its own axis. For example, when the arm is raised and rotated at the shoulder joint, it pivots around the axis of the arm.

This concept is fundamental in understanding joint mechanics and helps distinguish rotation from other types of movements, such as flexion, extension, abduction, or adduction, which involve changes in angles or positions relative to the midline of the body. The idea of movement around a single long axis allows for a clear understanding of how rotation enables specific movements, such as turning the head or twisting the torso, enhancing the complexity of human motion.