The aim of the following study was to investigate whether adult patients with mandibular retrognathism combined with a dental Class II relationship without craniomandibular pain show a characteristic structure of free mandibular movements caused by the neuromuscular system compared to patients with neutral skeletal and dental relationships. The authors also analyzed whether these characteristic structures changed following orthodontic-surgical treatment. To record the spatial movement of the mandible, an ultrasound measurement system was chosen and diagnostic software was developed for computer analysis of the recorded movements based on physical and biomechanical concepts. Clinically complaint-free, adult patients with mandibular retrognathism and distal bite exhibited a structure of mandibular movement that was markedly displaced as compared to patients with neutral skeletal and dental alignment. After completion of orthodontic and surgical treatment, it is apparent that the entire neuromuscular system of movement was transformed from one characterized by massive dyscoordination to one of harmonized, coordinated motion, as is seen in patients with nonpathologic, neutral relation.