A lateral knee X‑ray provides a side view of the knee showing the femur, tibia and patella, their alignment, and the joint space. It detects fractures, dislocations, patellar height/position, osteoarthritis signs (joint‑space loss, osteophytes), loose bodies, bone spurs and joint effusion (soft‑tissue swelling/fat‑pad displacement). It also assesses tibial plateau contour, posterior tibial slope and implant position.

Do you mean the criteria for ordering a knee X‑ray (Ottawa knee rules) or the clinical features/diagnostic criteria for lateral knee pain (eg, LCL injury, IT band syndrome, lateral meniscus)? Which one would you like summarized in 50–75 words?

A normal knee X‑ray shows intact, well‑aligned femur, tibia and patella with normal patellofemoral alignment and preserved joint space height, smooth articular surfaces, and no fractures, dislocations, bone lesions or significant osteophytes. Soft tissues appear unremarkable with no visible joint effusion. Mild age‑related changes may be minimal, but absence of narrowing, deformity or calcifications indicates no radiographic signs of arthritis or acute injury.

For a standard lateral knee radiograph the knee is flexed about 20–30° to relax tissues and allow femoral condyles to superimpose. The central X‑ray beam is typically angled 5–7° cephalad, directed to the knee joint (around the level of the medial femoral condyle) to best align with the joint space and reduce distortion.

A lateral knee problem is pain or dysfunction on the outer side of the knee, commonly caused by iliotibial band syndrome, lateral meniscal tears, lateral collateral ligament injury, bursitis, or lateral-compartment osteoarthritis. Symptoms include outer-knee pain, swelling, clicking, stiffness and instability. Diagnosis uses history, exam and sometimes X-ray or MRI. Treatment ranges from rest, ice, NSAIDs and physiotherapy to injections or surgery for severe cases.

Knee X-rays commonly show fractures, dislocations and bone alignment problems (varus/valgus). They detect osteoarthritis signs—joint-space narrowing, bone spurs, subchondral sclerosis and cysts. X-rays can reveal loose bone fragments or osteochondral defects, bone tumors and advanced infection changes. They do not reliably show soft-tissue injuries like ligament or meniscal tears, which usually require MRI.