Rasterstereographic functional examinations: Precision measurement of kyphosis and lordosis

Owing to the absence of radiation load, rasterstereography is suitable for virtually unlimited functional examinations. These examinations have two ma in purposes. First, measuring shape parameters in different postures enable s correlations between biomechanical quantities to be revealed. Second, onc e a standard posture has been defined, standardised parameters can be calcu lated. Depending on the number of contributing records, the accuracy of suc h standard values may be much higher than in the case of a single measureme nt. The procedure works for intentional gross posture changes as well as fo r unintentional minor posture sway. This is demonstrated for the kyphosis a nd lordosis angles in the case of anteversion and retroflexion. An addition al interesting aspect is the correlation of kyphosis and lordosis with trun k length and with each other. In the present study, a coupled motion betwee n kyphosis and lordosis was observed. On average, the kyphosis and lordosis angles changed nearly in parallel. A biomechanical explanation of this beh aviour is, however, not yet available.