Published online by Cambridge University Press: 05 July 2015
‘This is a radiograph of the right/left foot/ankle.’
• Ankle – AP (shows medial clear space), lateral and mortice view (shows lateral clear space more clearly)
• Foot – DP (dorsoplantar: equivalent to AP) and oblique
• Malleoli, talus, calcaneus, tarsal bones, metatarsal bones, phalanges
• Foot DP – 2nd metatarsal medial border lines up with medial border middle cuneiform.
• Foot oblique – 3rd metatarsal medial border lines up with medial border of lateral cuneiform.
• Ankle AP – talar dome line is smooth throughout.
• Ankle lateral – Bohler's angle (normal 28–40°). The angle formed by the intersection of a line drawn from the highest point of the posterior tuberosity to the top of the posterior facet, and a line from the top of posterior facet to the tip of anterior process of calcaneum. If reduced can signify an occult calcaneal fracture.
• March fracture: 2nd or 3rd metatarsal stress fracture.
• Inversion injuries: base of 5th metatarsal.
• Lisfranc injury: disruption of Lisfranc ligament with or without fracture leads to lateral displacement of the 2nd metatarsal base with respect to the middle cuneiform. Weight-bearing views very useful in unmasking subtle injury.
• If no obvious fracture is seen, look for signs of osteomyelitis; bone destruction/osteolysis, usually involving calcaneum, 1st/5th metatarsal heads or distal phalanges; or bone changes and deformities suggestive of Charcot foot, typically involving the tarsometatarsal joints.
• Look for metallic objects, nails or glass in the soft tissues.