Registration of natural head posture in children.

A method for registration of natural head posture is presented. The subject is photographed with contrast markers positioned on one side of the face and an adjacent plumb line as vertical reference. Systematic errors due to rotation and lateral tipping movements of the head were shown to be small and of no clinical importance. The measurement error in the transfer of the plumb line from profile photograph to lateral skull radiograph was shown to be small. Extension-flexion movements were found to have a standard deviation of 2 degrees about the mean in a group of patients between the ages of 12-14 years. Earlier studies show similar results for adults. The study supports the mirror-orientated registration of head posture viewed laterally in children as a biologically acceptable method.