What axis is involved when a person rotates their torso to look over their left shoulder?

When a person rotates their torso to look over their left shoulder, the movement occurs around the vertical axis, which is defined as the Y axis in biomechanics. This axis runs vertically through the body, allowing for rotational movements.

In this case, the rotation of the torso involves turning around this Y axis, causing the upper body to pivot in a horizontal plane. As the torso rotates, it allows the head to turn and align in the direction of the left shoulder, demonstrating axial rotation. Understanding the orientation and motion about the Y axis is crucial for analyzing and describing certain movements in biomechanics.