Blumensaat's line is a line which corresponds to the roof of the

intercondylar fossa of femur The intercondylar fossa of femur (intercondyloid fossa of femur, intercondylar notch of femur) is a deep notch between the rear surfaces of the medial and lateral epicondyle of the femur, two protrusions on the distal end of the femur (thigh bon ...

as seen on a

lateral Lateral is a geometric term of location which may refer to: Healthcare *Lateral (anatomy), an anatomical direction *Lateral cricoarytenoid muscle *Lateral release (surgery), a surgical procedure on the side of a kneecap Phonetics *Lateral cons ...

radiograph Radiography is an imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical radiography ("diagnostic" and "therapeut ...

of the

knee joint In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the hu ...

. 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 The patella, also known as the kneecap, is a flat, rounded triangular bone which articulates with the femur (thigh bone) and covers and protects the anterior articular surface of the knee joint. The patella is found in many tetrapods, such as m ...

, and so can be useful in diagnosing a broken femur as well as a

patellar tendon rupture Patellar tendon rupture is a tear of the tendon that connects the knee cap (patella) to the tibia. Often there is sudden onset of pain and walking is difficult. In a complete rupture, the ability to extend that knee is decreased. A pop may be felt ...

. It also helps to define "Schottle point" intra-operatively for reconstruction of MPFL(Medial patello-femoral ligament.) It may also be used to describe the course of an ACL graft.

References

Musculoskeletal radiographic signs {{Orthopedics-stub