Abstract: The invention relates to a method for determining the spatial position and orientation of the vertebrae hi a spinal column, comprising the following steps: taking at least one X-ray image of at least part of the spinal column; simultaneous recording of surface data (30) of at least one part of the back by means of an optical method; determining the position of elements in the bone structure by means of the X-ray image; determining the position of distinct elements (40) in the surface data; determining anatomical fixed points; superimposing the at least one X-ray taken and the surface data recorded by means of the anatomical fixed points; calculating a three-dimensional model (50) from elements of the bone structure from the surface data and the at least one X-ray image, wherein the 50 model contains the position and orientation of the vertebrae, the progression (55) of the spinal column and the spinal processes, as well as the shift (60) of the spinal process progression and the spinal column progression.