Which of the following muscles is considered the fixator during side lying leg abduction?

During side lying leg abduction, the muscle that serves as a fixator is important for stabilizing the pelvis so that other muscles can perform the movement effectively. In this scenario, the quadratus lumborum plays a crucial role.

The quadratus lumborum, located in the lower back, is responsible for stabilizing the pelvis and lumbar spine during lateral movements. As the leg is abducted, maintaining pelvic stability is essential, allowing the gluteus medius and minimus to engage more effectively to lift the leg.

The other muscles listed, such as the tensor fascia latae, gluteus maximus, and gluteus minimus, primarily function as agonists or synergists during the movement, contributing directly to leg abduction. However, it is the quadratus lumborum that acts as the stabilizing fixator, ensuring that the body remains balanced and properly aligned as the leg is raised away from the midline. This stabilization prevents unnecessary pelvic tilt and allows for a more effective and controlled abduction movement.