What example illustrates movement around the Z axis in a positive direction?

Movement around the Z axis refers to rotational movements, which typically occur in a horizontal plane. When considering the positive direction of movement around the Z axis, it's important to visualize the body's movements in terms of rotation.

In the context of lateral flexion of the trunk, right lateral flexion involves the trunk bending sideways towards the right side. This bending can be visualized as a rotation around the Z axis. Positive movement around the Z axis often correlates with a rotation in a counterclockwise direction from an anatomical perspective. However, when focusing on bending to the right side, it clearly demonstrates rotation in a lateral direction, which aligns with how lateral flexion is defined.

In contrast, trunk flexion involves forward bending, which primarily occurs around the X axis and does not illustrate movement around the Z axis. Left lateral flexion is the opposite action and would be considered in the negative direction as it involves bending towards the left side rather than the right. Trunk rotation generally refers to twisting around the vertical axis and is not specifically indicative of movement to one side like lateral flexion is.

Thus, right lateral flexion effectively exemplifies movement around the Z axis in the positive direction due to the specific rightward lateral bending of the trunk.