Acetabular transverse and posterior wall fractures

(A) The appearance on the anteroposterior view is similar to that of a pure transverse fracture with disruption of five of the six radiograph landmarks; only the radiographic U (which maintains its normal relationship to the ilioischial line) remains intact. The posterior wall fragment is seen as an oblique cortical line overlying the intact roof (arrow).
(B) The obturator oblique shows the transverse fracture, the subluxation of the femoral head with the ischiopubic fragment, as well as the posterior wall fragment. It is easy to see on this view how the femoral head may abrade against the fracture edge while the hip is subluxated.
(C) The iliac oblique view highlights the fracture line exiting the greater sciatic notch as well as the posterior wall fragment superimposed on the roof of the acetabulum (arrowhead).
(D) This computed tomography section shows the posterior wall fracture (dashed arrow) with a column fracture line typical of a transverse fracture (double arrow).