-The objective of this study was to assess the effects of asymmetric placement of the foot on the three-dimensional motions of the interphalangeal joints. Four isolated forelimbs were used. Trihedrons, made of three axes fitted with reflective markers, were screwed into each phalanx. They allowed to establish a local frame associated with each bone and thus to define the spatial orientation of the phalanges. The limbs were then placed under a power press, and subjected to compression with gradually increasing force (from 500 to 6 000 N). The procedure was performed in neutral position and with the lateral or medial part of the foot raised by a 12 o wedge. Flexion, collateromotion (passive abduction/adduction) and axial rotation of the interphalangeal joints were measured using a cardan angle decomposition according to the principle of the "Joint Coordinate System" described by Grood and Suntay. Raising the lateral or medial part of the hoof induced collateromotion (about 5.6 o ± 0.8) and axial rotation (about 6.5 o ± 0.5) of the distal interphalangeal joint. The proximal interphalangeal joint underwent axial rotation (about 4.7 o ± 0.5 at 6 000 N) and slight collateromotion. Both interphalangeal joints underwent collateromotion in the direction of the raised part of the foot (i.e., narrowing of the articular space on the side of the wedge), whereas axial rotation occurred in the direction opposite to the raised part of the foot. These results confirm the functional importance of interphalangeal joint movements outside the sagittal plane. In particular they demonstrate the involvement of the proximal interphalangeal joint in the digital balance. These data are helpful for the identification of biomechanical factors that may predispose to interphalangeal joint injury. Also the data may be of use for the rational decision making with respect to exercise management and corrective shoeing of the lame horse. Résumé -Étude cinématique tridimensionnelle des articulations interphalangiennes chez le cheval: influence de l'appui asymétrique du pied. L'objectif de cette étude était de déterminer les effets de l'appui asymétrique du pied sur le comportement tridimensionnel des articulations interphalangiennes. Quatre membres isolés ont été utilisés. Des systèmes de suivi cinématique, pourvus de 3 axes portant des marqueurs réfléchissants ont été vissés dans chaque phalange. Ces systèmes permettaient de déterminer, pour chaque segment osseux, un repère local définissant l'orientation du segment. Les membres ainsi équipés étaient placés sous une machine de compression et soumis à des cycles de mise en charge de 500 à 6 000 N, en modifiant l'orientation du sabot par l'apposition d'une cale de 12 o sous le quartier latéral ou médial. Les angles de flexion, collatéromotion (abduction/adduction passive) et rotation axiale des articulations interphalangiennes ont été calculés selon le principe du « Système d'Axes Articulaires » énoncé par Grood et Suntay. Les modifications de l'appui transversal du pied ont provoqué un mou...