Purpose: To determine the extent to which the width of the space in the medial tibiotalar joint depends on plantar flexion.
Material and methods: Thirty healthy volunteers were studied by means of a.p. roentgenograms of the left ankle both in a neutral position and in plantar flexion.
Results: The medial joint space showed significant widening (average 0.65 mm) between the neutral position and plantar flexion.
Conclusion: When ankle joint injuries are studied on radiographs, the position of the foot must be taken into consideration.