What is the purpose of the acetabulum in the coxal bone?

The pectoral and pelvic girdle bones help in the articulation of the upper and the lower limbs respectively with the axial skeleton.Each half of the pectoral girdle consists of a clavicle and a scapula. The acromion is a slightly elevated ridge in the scapula that projects as a flat, expanded process and articulates with the clavicle.The acetabulum is a cavity at the point of fusion of the ilium, ischium and pubis in the coxal bone and articulates with the thigh bone.The human body consists of 206 bones in total. These bones are grouped into two main divisions - the axial skeleton and the appendicular skeleton. The skull is composed of two sets of bones, cranial and facial, that total to 22 bones.Each vertebra has a central hollow portion (neural canal) through which the spinal cord passes. The vertebral column is differentiated into cervical (7), thoracic (12), lumbar (5), sacral (1-fused) and coccygeal (1-fused) regions.