By far the most numerous of the ankle fractures are those of the malleoli, medial as in image 1, and more commonly, lateral as in images 2 and 3 and 4. It can be seen in image 2 that some of these malleoli fractures can be a little difficult to see as they are often undisplaced or minimally displaced. There are no definite soft tissue signs to look for as in the elbow or knee, but generally there will rarely be a fracture of one or both of the malleoli without soft tissue swelling around it. However the presence of soft tissue swelling is not a guarantee of a fracture, far from it. The reporter just has to make sure they check for the steps in the cortex as in image 3 or any disruption of the trabeculae as in image 4.

Always remember that it is not just the bones that should be checked but the joint spaces also. Images 5 and 6 show a fracture of the distal fibula but in this case there is some subluxation of the tibio-talar joint anteriorly and medially. Images 7 and 8 show a bimalleolar fracture where both medial and lateral malleoli are fractured, and again there is some tibio-talar joint disruption. Always check for uniformity of the joints.

Images 9 and 10 show the trimalleolar fracture which, as it's name suggests, are fractures of the medial and lateral malleoli along with the posterior malleolus which is the posterior aspect of the distal tibia. This usually, but not always, involves a dislocation of the ankle joint. Fortunately for the patient but unfortunately for the quality of the images this ankle had already been put into a back slab. The fractures of the medial and lateral malleoli can be seen on the A.P. view in image 9, and the fracture of the posterior malleolus on the lateral view in image 10. Image 11 is also a trimalleolar fracture which is more obvious on the A.P. view as the postero-lateral border of the tibia can be seen to be displaced.

Images 12 and 13 show what can happen when the main injury is to the distal shaft of the tibia. If the distal tibia is fractured with a lateral twisting motion this will transfer that twisting force to the talus and the fibula. This twisting force on the fibula can then cause it to fracture at the proximal end. This is known as a Maisonneuve fracture. This can in some cases happen in reverse when the initial injury is to the knee resulting in fractures of the proximal tibia and distal fibula.

The bones of the ankle are prone to avulsion fractures as in images 17 and 18 which are quite rare avulsion fractures from the anterior tibia and posterior aspect of the medial malleolus, respectively. However the ankle is also a good area to find accessory ossicles which on occasion can resemble avulsion fractures. Images 19 and 20 are good examples of this. Image 19 is an avulsion fracture of the lateral aspect of the distal fibula while image 20 shows an accessory ossicle (some would argue, an intercalary bone or sesamoid) which appears within the talo-fibula joint, and being elongated in appearance gives the impression of an avulsion. As always check for cortication. If the reporter believes that there is a cortex all around the fragment then it is likely to be an ossicle, if not it may be an avulsion.

Images 21 and 22 show the os sub fibulare. On occasions this ossicle can be quite large as in image 23, and quite confusing looking more like a fracture on the lateral, as in image 24.

One avulsion that should not be possible to miss is that of the Achilles tendon insertion at the postero-superior aspect of the calcaneum as in image 28. It is just possible to see in the soft tissues in this image the way the tendon has coiled up above the avulsed fragment.

One very important point to remember about the technique used when radiographing the traumatized ankle is that the lateral view should always include the base of the fifth metatarsal. It is very common for inversion injuries of the ankle to result in a fracture of the base of the fifth metatarsal, with or without ankle joint fractures see image 29. Therefore if the base of fifth is included on the lateral ankle view, the possible fracture can be excluded, or demonstrated, without the need of further radiation. It is not good practice to radiograph the foot after demonstrating the base of fifth fracture on the ankle view just to get further views of the fracture.

Images 30 and 31 show two accessory ossicles of the talus which are often mistaken for fractures. Image 30 shows the os trigonum at the posterior talus and image 31 shows the os supra-talar on the anterior aspect of the talus. Os trigonum once learned is always fairly obvious, os supra-talar on the other hand nearly always resembles an avulsion fracture. As before, is it corticated? Check also image 25 which shows the os trigonum projected into the talo-fibula joint space on a not so good A.P. view.

Getting into the realms of the foot but often seen on the lateral ankle is the os supra-naviculare, image 32. In this image the os supra-naviculare is more proximal than usual and is partially incorporated into the navicular. Image 33 shows a larger os supra-naviculare.

Image 34 shows a high secondary calcaneal apophysis and images 35 and 36 show the more usual appearances of the calcaneal apophysis. Note that it can be a single ossification or multiple. Of course the calcaneum is more foot than ankle but it is often seen on the ankle radiographs and inexperienced doctors without the benefit of a radiographers report may refer the patient for more x-rays.

Images 37 and 38 show the appearances of "Harris Lines". These are areas of increased density laid down at the then metaphysis, during periods of growth retardation, which often occur during childhood illness. They are quite common and are often multiple, can be seen in any of the long bones but appear more frequently in the distal tibia. They remain in the bone forever and can be seen in radiographs of skeletons from archaeological digs. They should not be confused with impacted fractures which are unlikely to occur perpendicular to the length of the bone and relatively distant from the articulation.