Blumensaat's line is a line which corresponds to the roof of the intercondylar fossa of femur as seen on a lateral radiograph of the knee joint. The angle at which this line appears on the radiograph can be used to determine the position of the patella or diagnose an ACL injury.
Clinical Use
On a normal radiograph, the line intersects the inferior pole of the patella, and so can be useful in diagnosing a broken femur as well as a patellar tendon rupture.
References
Blumensaat's line Wikipedia(Text) CC BY-SA