The AP view of the knee is an anteroposterior X‑ray projection with the beam directed front-to-back through the joint. Performed supine or standing (weight-bearing when assessing alignment/osteoarthritis), the knee is usually extended and the beam centered at the joint line. It visualizes the distal femur, proximal tibia, joint space and alignment, helping detect fractures, joint space narrowing and degeneration.

The price of an AP and lateral knee X‑ray varies by country and facility: in India private diagnostic centers typically charge about ₹200–₹800; in the UK it is free via public care but private clinics may charge about £30–£80; in the US self‑pay costs roughly $50–$250 (hospital fees can be higher). Extra views or radiologist reporting may add fees—check local centres and insurance.

An AP weight-bearing knee X-ray is an anteroposterior radiograph taken while the patient stands with weight on both legs. It evaluates joint space, alignment, osteoarthritis severity, and varus/valgus deformity, revealing load-dependent narrowing that may be missed when supine. The exam is quick, aids diagnosis and treatment planning, and carries only low radiation exposure.

An AP (anteroposterior) leg is an X‑ray taken from front to back that shows a frontal view of the lower leg—typically tibia, fibula and adjacent knee and ankle. Performed supine or standing and often paired with a lateral view, it helps assess fractures, bone alignment, joint spaces, hardware position and leg‑length or alignment problems.

Apophysitis is inflammation of an apophysis (a growth-plate tendon attachment) often affecting the knee in adolescents—examples include Osgood–Schlatter disease (tibial tubercle) and Sinding‑Larsen‑Johansson (inferior patella). It causes localized pain and swelling worsened by running or jumping. Management is conservative: activity modification, ice, stretching/strengthening physiotherapy, and analgesics; symptoms usually resolve after skeletal maturity.

AP (anteroposterior) view is obtained when the X‑ray beam passes from the front to the back of the patient. Position the patient so the anterior chest/area faces the tube with the detector behind the back (standing, sitting or supine). Center the detector over the region of interest, align the central ray perpendicular, apply correct exposure and markers, and instruct breath‑hold if needed.