ABSTRACT:A simple radiographic apparatus standardizing foot position and simulating weight-bearing effects in the feet is described in this paper. It provides an effective means of obtaining reliable radiographic data for both ambulatory and nonambulatory patients. This device is presently used in an on-going study on pes cavus in Friedreich's ataxia. RESUME: Un appareil radiographique simple a utiliser normalisant la position des pieds et simulant I'effet du poids du corps est d6crit dans cet article. II permet d'obtenir de maniere efficace des donnees radiographiques fiables chez les patients ambulants ou non. Cet appareil est pr6sentement utilise dans I'etude du pied creux chez les patients atteints d'ataxie de Friedreich.Can. J. Neurol. Sci. 1984; 11:574-577 Radiographs are commonly utilized to confirm the presence and to assess the extent of foot deformities. Most often the clinician makes use of dorsiplantar (DP) and lateral (LAT) radiographs by marking on them reference lines and angles to document the state of the bony configuration and to quantitatively measure the observed deformity.Standing radiographs are preferred since the weight-bearing attitude of the feet allows appraisal of the structural component of the deformity as opposed to the positional or reducible elements of the feet. Furthermore, in the case of a unilateral affliction, it allows comparison with the contra-lateral extremity being positioned and solicited in a similar manner (Gamble and Yale, 1975). Conventionally dorsiplantar radiographic views as described by Kreed (1979) are obtained when the foot is bearing the full weight of the body with its plantar aspect in contact with the X-ray cassette or with the foot assuming a similar position when the patient is sitting, semi-recumbent or supine. The X-ray beam is usually centered over the second and third rays perpendicular to the film plate. To avoid the bony superimposition of the tarso-metatarsal joints the radiographic source is tilted by approximately 15° towards the ankle joint. An alternative technique is to simply raise the forefoot by 15° by inserting a wedge under the film cassette while keeping the X-ray source perpendicular to the table or ground level. Once the feet are positioned, the DP radiograph can then be taken.To obtain a weight-bearing LAT radiograph of the feet, the patient is asked to stand on low leveled and radiotranslucent platform. Two film plates separated by a lead sheet are placed vertically between the feet and ankles while resting on the platform. The patient's feet are then positioned close together and in contact with the film packs. For each foot the LAT radiographs are taken individually and consecutively. With an horizontal tube projection, the X-ray beam is centered on the lateral aspect of the navicular-cuneiform region.For a non-weight bearing LAT radiograph obtained in the sitting or semi-recumbent position, the patient's legs are placed in the "frog position" with the lateral aspect of the feet lying directly on the film cassette. Fig. 1 illu...