Posterior hip dislocations cause the leg to be flexed at the hip, adducted toward the midline, and internally rotated. This happens because the femoral head is displaced backward out of the acetabulum, often after a force to the knee or dashboard-type injury, pulling the leg into that flexed, cross-legged position. The limb is usually shortened as well, reflecting the displacement of the hip joint. This pattern differs from anterior dislocations, where the leg tends to be extended (or flexed), abducted, and externally rotated. So the description of flexion, adduction, and internal rotation best matches the post-dislocation position.

The key idea is using a dynamic, weight-bearing maneuver that specifically stresses the meniscus to reproduce symptoms. The Thessaly test does this by having the patient stand on one leg and slowly rotate the knee while it’s flexed at about 5 degrees and then at 20 degrees. If there’s a meniscal tear, the twisting under load often causes joint-line pain, a sense of catching, or locking. It’s a quick, simple way to assess meniscal integrity in a clinic setting. Other maneuvers can test meniscal pathology too, but they’re less direct or not focused on the meniscus. The Apley compression test also targets the meniscus but is performed with the patient lying face down and can be less specific. The Lachman test evaluates the anterior cruciate ligament rather than the meniscus, and McMurray is the classic test already noted. Thus, the Thessaly test stands out as the best additional maneuver for diagnosing a meniscal tear.

For a lateral knee projection, you want the knee to be flexed only lightly so the femoral condyles can be superimposed and the tibia aligned under the femur. This position keeps the femorotibial joint space open and the patella in profile, producing a true lateral view. About 20 degrees of knee flexion achieves this balance: it places the knee in proper alignment without excessive rotation, giving a clean lateral image with accurate joint visualization. Very little flexion (around 5 degrees) wouldn’t allow true lateral superimposition, and too much flexion (like 45 or more) would alter the relationships and obscure the joint details. A 20-degree bend is the standard that yields the best lateral knee image.

Monteggia fracture is defined by a fracture of the proximal ulna with dislocation of the radial head at the radiocapitellar joint. This pattern is what radiographs typically show: the ulna broken near the elbow and the radial head displaced relative to the capitulum, often anteriorly in children. The other scenarios involve fractures at the distal forearm or fractures of the radius itself, which do not match the classic Monteggia combination.