Computer modelling of human partial body structures is becoming increasingly important for medical application. This is an interdisciplinary field of research in which new methods can be developed through the cooperation of physics, mathematics, computer visualistics and medicine. These methods can be used to make more precise statements about the mechanical loads of internal force-transmitting structures, such as intervertebral discs, ligaments, joints and muscles, during motion sequences. At the beginning of this work, the importance of the need for research in computer modeling, specialized in the area of the spine, is presented. In the following, the basic anatomical structures will be discussed, including intervertebral discs, ligaments, facet joints and musculature. Algorithms are then developed to create individual lumbar spine models from CT data in a short time and semi-automatically. Methods will be developed to model the presented force transmitting structures of the spine, such as the intervertebral discs, ligaments, facet joints and muscles. In addition different imaging methods (MRT data, x-ray film, x-ray functional images) will be presented and validate the lumbar spine models. Finally, the algorithms developed will be used to create a larger number of individual lumbar spine models, which will then be examined for similarities and differences with regard to internal loads as well as for physiologically correct movement sequences. In particular, the relative momentary center of rotation between two adjacent vertebrae is calculated.