Various studies have documented a variability of hyoid bone position in
relation to changed mandibular position or head posture. The aim of this
study was to investigate the hyoid bone position and inclination on the
cephalometric radiographs of two groups of patients exhibiting Class I
and Class III malocclusions. The radiographs were taken in both centric
occlusion and wide-opened mandibular position, and 17 measurements were
performed on both tracings. The findings reveal a statistically
significant difference in the position and inclination of the hyoid bone
in the two groups; Class III patients, especially the boys, show a more
anterior position of the hyoid bone and also a reverse inclination. This
might have an implication on the function of the suprahyoid and
infrahyoid muscles and thus on the direction of mandibular growth
