Perkin's line

a vertical line drawn downward from the lateral rim of the acetabulum, which forms part of a system of lines used in the radiographic evaluation of hip alignment. The intersection of Perkin's line with the line of Hilgenreiner (Hilgenreiners line) divides the hip into four quadrants, which aids in establishing the diagnosis of lateral migration of the femoral head in patients with developmental dysplasia of the hip DDH .

DR