Ankle
- Ottawa ankle rules: radiograph if malleolar pain plus bone tenderness at the posterior edge or tip of either malleolus (distal 6 cm) or inability to bear weight (4 steps). Foot series if tenderness at the base of the 5th metatarsal or navicular.
- Views: AP, lateral, mortise (15° internal rotation: medial clear space ≤ 4 mm, uniform joint space).
- Weber classification (level of fibular fracture relative to the syndesmosis): A below (stable, infrasyndesmotic), B at the level (trans‑syndesmotic; stability depends on medial side), C above (suprasyndesmotic; syndesmotic disruption, unstable). Lauge‑Hansen (mechanism).
- Bimalleolar / trimalleolar (medial + lateral + posterior malleolus of the tibia): unstable → ORIF.
- Maisonneuve fracture: proximal fibular fracture + syndesmotic and medial (deltoid/medial malleolus) injury: image the whole fibula if medial clear space is widened without a distal fibular fracture.
- Pilon fracture: axial load comminution of the tibial plafond (CT).
- Tillaux (adolescent, Salter III of the anterolateral distal tibial epiphysis) and triplane (Salter IV in three planes) fractures: transitional fractures of adolescence (CT).