Which muscle is a synergist to lateral rotation of the hip?

The gemellus inferior is indeed a synergist in lateral rotation of the hip. This muscle is located deep in the gluteal region and works in conjunction with other muscles of the hip such as the piriformis and gemellus superior to facilitate this movement.

In lateral rotation, the muscle fibers of the gemellus inferior contract and help to rotate the femur laterally in the hip joint. Being a synergist means it assists the primary movers in this action, enhancing the effectiveness of their contraction and allowing for a smooth and coordinated movement.

Understanding the roles of muscles in actions like hip rotation is crucial for therapeutic practices and athletic training, as it informs which muscles to strengthen or stretch for improving performance or preventing injuries.