Final answer:
Rotational movement is the rotation of a bone around its own axis, as seen in the motion of shaking the head 'no' or the pronation and supination of the forearm.
Step-by-step explanation:
Rotational movement refers to the movement of a bone as it rotates around its longitudinal axis. This kind of motion can occur in different joints in the body, including the vertebral column, pivot joints, and ball-and-socket joints. A common example of rotational movement is when you rotate your head from side to side as if shaking your head "no." This is made possible by the atlantoaxial joint, a pivot joint, allowing the first cervical vertebra (atlas) to rotate around the second cervical vertebra (axis).
Other examples of rotational movement include the pronation and supination movements of the forearm, which occur at the proximal radioulnar joint. Pronation involves the palm facing downward, while supination is when the palm faces upward. Rotational movement can be either medial – toward the body's midline – or lateral – away from the body's midline.
Movements like flexion and extension are examples of angular movements, which differ from rotational movements in that they involve changing the angle between bones of a joint rather than rotating a bone on its axis. Such movements contribute to the complex mechanics of the human body that allow a vast range of movements.