Description
The acetabulum is the cup-shaped cavity on the outer aspect of the coxal bone. It is formed by the fusion of the ilium, ischium and pubis, where:
—its anterior one fifth is formed by the superior ramus of pubis;
—its posterosuperior two fifths is formed by the body of ilium;
—its posteroinferior two fifths is formed by the body of ischium.
It is circumscribed by a prominent edge, the acetabular margin, which is absent inferiorly, leaving a gap that is known as the acetabular notch. Within the acetabulum lies its articular and non-articular portions:
—The articular portion is formed by the peripherally located lunate articular surface, which articulates with the head of femur, forming the hip joint.
—The non-articular portion is formed by the centrally located acetabular fossa, which forms the floor of the acetabulum.