line of Klein
The line of Klein describes a line along the superior edge of the neck of the femur. It is useful in detecting early slipped upper femoral epiphysis in adolescents. The line should normally intersect the lateral part of the superior femoral epiphysis. If the line of Klein fails to intersect the epiphysis during the acute phase, it is called Trethowan sign . In very subtle cases, asymmetry between the lines of Klein might be the only way of determining a slipped upper femoral epiphysis.