It is part of the posterior column of the acetabulum. The ilioischial line of Köhler begins at the medial border of the iliac wing and extends along the medial border of the ischium to end at the ischial tuberosity.It conforms to the inner margin of the pelvic ring and it is part of the anterior column of the acetabulum. The iliopectineal or iliopubic line is formed by the arcuate line of the ilium and the superior border of the superior pubic ramus up to the pubic symphysis.In newborns, values of in males and in females are considered normal. It is formed between Hilgenreiner line and the acetabular roof.

It is the most useful measure of acetabular dysplasia until 6 years of age. (D) The acetabular index measures the acetabular roof slope.However, in infants this line can be unreliable as it depends on the rotation of the hip when the image is taken. In children over about 3 to 4 years of age, this line should be smooth and undisrupted, otherwise it may indicate a fracture or hip dysplasia. (C) Shenton line is a continuous arc drawn from the inner edge of the femoral neck to the superior margin of the obturator foramen.The value for patients under 3 years must be 0 and in older children this ranges from 0 to 22%. We can measure the lateral displacement of the femoral head with regard to the Perkin line by dividing the width of the head that crosses the Perkin line by the diameter of the head. This leads to four quadrants and a normal femoral head has to be located in the inferomedial quadrant. (B) Perkin line is perpendicular to Hilgenreiner line, touching the lateral margin of the acetabular roof.This line is used to measure the acetabular angle and as a reference for Perkin line. (A) Hilgenreiner line, connects the inferior tips of the iliac bones, at the triradiate cartilage.The most useful lines and angles that can be drawn in the pediatric pelvis assessing hip dysplasia are as follows: The range of normal values is from 90 to 135° and is related to the infant’s age. Lines are drawn from the highest point of the ischium to the most prominent point of the symphysis, joining at the inside of the pelvis. Symphysis os-ischium angle (of Tönnis): This evaluates the pelvic position in the sagittal plane.In neutral rotation the ratio is 1 but is considered to be acceptable when it is between 0.56 and 1.8. Obturator foramen diameter ratio (of Tönnis): A quotient of pelvic rotation by dividing the horizontal diameter of the obturator foramen of the right side and that of the left.Reliability of measurements increases if indicators of pelvic alignment are taken into account: Unfortunately the time the joint gives a good x-ray image is also the point at which nonsurgical treatment methods cease to give good results.Ĭhildren Image quality checking Image quality checking. When the infant is around 3 months old a clear roentgenographic image can be achieved. Ultrasound imaging yields better results defining the anatomy until the cartilage is ossified. X-rays of hip dysplasia are one of the two main methods of medical imaging to diagnose hip dysplasia, the other one being medical ultrasonography.

Normal hip joint anatomy xray