Figure 5From: Digital anatomical measurements of safe screw placement at superior border of the arcuate line for acetabular fracturesTo section 4, the length of screw d 1 and the angleαwere measured with the method same as section 2 and 3. The line tangent to the arc of quadrilateral surface through the screw entrance was recorded as the length of screw, d2. The angle between the tangent line and the normal plane was recorded as β.Back to article page