Which muscle primarily abducts the thigh?

The gluteus medius is the primary muscle responsible for abducting the thigh. This muscle is located on the lateral aspect of the hip and acts to pull the thigh away from the midline of the body. When the gluteus medius contracts, it stabilizes the pelvis during walking or running and facilitates lateral movement of the leg.

While the tensor fascia latae also plays a role in thigh abduction, its contribution is not as significant as that of the gluteus medius. The vastus medialis and rectus femoris muscles are primarily involved in extending the knee and flexing the hip, respectively, rather than in thigh abduction. Therefore, the gluteus medius is recognized as the key muscle in this action, making it the correct answer for the question about which muscle primarily abducts the thigh.