The point of deepest concavity on the lateral border of the femoral neck is marked.Īnother arc through that point using the center of the femoral head as the center is drawn. Reference points for the circular arc are the lateral portion (outermost point) of the epiphysis and the medial corner of the femoral neck. The center of the femoral head is located with a circle template or a computer-assisted technique. Müller uses the following method for an accurate reconstruction of the NSA: A line drawn perpendicular to that line through the center of the femoral head represents the femoral neck axis. Next a line is drawn connecting the points where the circle intersects the medial and lateral borders of the femoral neck. 2.3): first the center of the femoral head is located with a circle template or computer-assisted technique at a workstation. The femoral neck axis can be determined as follows ( Fig. 1 = Iliopectineal line 2 = Ilioischial line 3 = Acetabular roof line 4 = Acetabular teardrop 5 = Posterior rim of acetabulum 6 = Anterior rim of acetabulum a Schematic drawing. Anatomic landmarks for evaluating the hip in the anteroposterior pelvic radiograph. It is the angle formed by the longitudinal axes of the neck and shaft of the femur. 2.2) is determined on the anteroposterior (AP) pelvic radiograph or the AP radiograph of the hip and femur. The projected femoral neck–shaft angle (NSA, called also the caput–collum–diaphyseal (CCD) angle Fig. The quadrilateral plate is the posterior wall of the acetabulum, which faces inward on the pelvic inlet and presents an approximately square, flat surface.Īrmbuster TG, Guerra J Jr, Resnick D, et al. The ilioischial line is the landmark for the posterior column.Īcetabular teardrop: This is a teardrop-shaped figure formed laterally by the medial portion of the acetabulum and medially by the antero-inferior portion of the quadrilateral plate. Ilioischial line: The upper portion of this line is formed by the posterior part of the quadrilateral plate, its lower portion by the ischium (medial boundary). Iliopectineal line (arcuate line, linea terminalis): The iliopectineal line is the radiographic reference line for the anterior column. The following radiographic landmarks and their interrelationships are helpful in diagnosing congenital and acquired abnormalities of the acetabulum ( Fig.