Anteroposterior (AP) pelvic radiographs only give a 2D projection of what is a 3Dshape. Depending on the position of the patient while the radiograph is taken, the 2Dprojection of the shape may vary. This paper investigates the short-term variability ofprojected proximal femur shape using AP pelvic radiographs. We train a statistical shapemodel of the proximal femur based on a set of 87 radiographs–42 of which represent 21pairs of two radiographs per person taken at two different sessions on the same day. These21 pairs allow us to use the parameters of the shape model to analyse the within-personvariation of projected proximal femur shape. We demonstrate that the within-personvariation is small compared to the overall shape variation of the proximal femur given byall 87 radiographs. This work underlines the suitability of AP pelvic radiographs–eventhough only giving a 2D projection–for the analysis of the relationship between proximalfemur shape and diseases such as osteoarthritis or osteoporosis.