Final answer:
A complete articular acetabulum fracture occurs when there is a separation of the attachment between the articular surface and the posterior ischium.
Step-by-step explanation:
A complete articular acetabulum fracture occurs when there is a separation of the attachment between the articular surface and the posterior ischium. The acetabulum is the socket portion of the hip joint and is formed by the convergence of the ilium, pubis, and ischium. When this attachment is disrupted, it can result in instability and impaired function of the hip joint.