Introduction: In this thesis we have determined how the imaging of the ankle in medial and lateral projections with different inclination of the x-ray tube and differently directed central beam affects the representation of anatomical structures. We determined which projections are most useful for the representation of a given structure and the differences between layout and evaluation criteria. Aim: The aim of the thesis was to determine how the change of position affects the visibility of anatomical structures and which projection is most useful for representing a given anatomical structure. Work methods: Measurements were made on a phantom foot marked RS -116. We started with a 5 degree rotation of the ankle in medial direction, to anthroposterior projection with medial rotation, later to medial posterior oblique projection, changing the central beam. The same was continued in the lateral direction, where we added a cranial angle in lateral posterior oblique projection. We then changed the central beam from 5 to 20 degrees cranially and caudally. Each x-ray image was evaluated according to the criteria for its assessment. The results: While rotating the ankle joint in a medial direction we could observe that the upper ankle joint is fully opened and then gradually begins to close. The talus protrudes up to the metatarsal bones. In medial posterior oblique projection, the central beam initially runs 10 degrees caudally. The upper ankle joint is almost completely open and the metatarsals partially overlap. We can assess the calcaneus and the talus. As the angle increases, calcaneus is completely free, the joints are partially open and the smaller bones overlap. In the lateral posterior oblique projection we see open joints between calcaneus and talus as well as talus and talus articulation. When the x-ray tube is tilted in caudal direction, the upper ankle joint is gradually closed by adding the angle of inclination, the talus is partially freely projected. When the tube is tilted cranially, the upper ankle joint is closed. All other bones are superimposed and overlap each other. Discussion and conclusion: Anthroposterior projection is recommended when assessing the upper ankle joint, talus, distal part of the scapula and tibia. Medial posterior oblique projection is recommended for evaluation of the talus, calcaneus and the cuboid bone. Lateral posterior oblique projection is used to show the lower ankle joint, calcaneus, talus and part of the metatarsal bones. The caudal inclination of the tube is best suited to assess the talus, while the cranial inclination of the tube is diagnostically useless in this case.
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