Right trunk rotation occurs around the Y axis in which direction?

• A. Positive
• B. Negative
• C. Anterior
• D. Posterior

Answer: (B)

Right trunk rotation occurs around the Y axis in a negative direction. In biomechanics, when discussing movement around an axis, positive and negative directions are often defined based on the right-hand rule. When you point the thumb of your right hand in the direction of the positive Y axis (typically upward), the fingers curl in the direction of positive rotation.

For the trunk, right rotation means that the front of the body (the sternum) rotates toward the right side when viewed from above. In this context, this clockwise rotation is defined as a negative rotation. Understanding this concept is crucial for analyzing and interpreting body mechanics accurately in clinical practice, as it will help with assessing movement patterns and potential issues related to trunk rotation.