Is ilium one of the bones pelvic girdle?

Yes, the ilium is one of the three bones that make up the pelvic girdle. The pelvic girdle, also known as the hip bone, is a ring-shaped structure that connects the lower limbs to the axial skeleton. It consists of three paired bones: the ilium, ischium, and pubis. The ilium is the largest and most superior of the three bones and forms the upper and posterior portion of the pelvic girdle. It articulates with the sacrum posteriorly and with the pubis and ischium anteriorly. The ilium contributes to the formation of the hip joint, which is a ball-and-socket joint between the head of the femur and the acetabulum, which is formed by the fusion of the ilium, ischium, and pubis.