Final answer:
The three gluteal lines on the ilium are the posterior, anterior, and inferior gluteal lines, which serve as attachment sites for the gluteus maximus, medius, and minimus muscles, respectively.
Step-by-step explanation:
The three gluteal lines on the ilium of the hip bone are important landmarks for the attachment of the gluteal muscles, which are critical for movement and stability of the hip joint. They consist of the posterior, anterior, and inferior gluteal lines. The posterior gluteal line is the most posteriorly positioned, the anterior gluteal line is located anteriorly, and the inferior gluteal line is the lowest of the three. These lines serve as sites of attachment for the gluteus maximus, medius, and minimus muscles, respectively. These muscles play vital roles in extending, abducting, and rotating the femur at the hip joint, as well as maintaining posture.