Break in SL. SL is an imaginary curved line drawn along the inferior border of the superior pubic ramus along the inferomedial border of the neck of the femur. Break in SL is defined as plus (mm) when the inferomedial border of the neck of the femur moves above the inferior border of the superior pubic ramus. The white arrow between the two lines indicates a break in SL with a plus value. SL = Shenton's line.