Last updated on August 1 2024
Description
The angle of inclination of the ossified acetabular roof is measured on an AP radiograph of the pelvis. This value is considered an estimate of acetabular development. The most commonly used method for measuring this angle is the “Caffey's method”. To do this, a horizontal line is drawn connecting the upper edges of the radiolucent Y-joints. Another line is then drawn from the superolateral border of the ossified acetabulum to the superolateral border of the Y kerf. The angle between the two lines is usually less than 30° in newborns and less than 20° in two-year-olds.
Measurements
- Acetabular Angle (R): the angle between the Hilgenreiner line and Acetabulum to superolateral border line on the right side.
- Acetabular Angle (L): the angle between the Hilgenreiner line and Acetabulum to superolateral border line on the left side.
Auxiliary references
- Hilgenreiner’s line: a horizontal line through the triradiate cartilage of the acetabulum;
- Acetabulum to superolateral border lines (left and right): a line drawn from acetabulum back wall to the triradiate cartilage (left and right).
How to perform
After selecting this procedure in the sidebar, you must mark the points to conclude it. To see the caption of each point you need to click on this button 
Beware: You can change the position of the points at this stage or later. To do this, simply click on each handle with the left mouse button and move them to the most suitable position.
This procedure has no advanced configuration.