Modern orthodontics take into account of balance between dentofacial complex as a whole and the position of hyoid bone in different Angle’s class malocclusion has intrigued and attracted many researchers. The hyoid bone is unique in that it has no bony articulation with any other bone but is instead suspended in the soft tissue via ligaments and muscles (Romanes et al 1983). Different muscles such as infra and suprahyoid muscles and genioglossus muscle influence the position of the hyoid bone (Gray H, 1954) (Yamaoka et al 2003).
Brodie points out that as man assumed an upright posture the head had to be balanced on the vertebral column. This is attained by equal anterior and posterior muscle tension relative to the occipital condyles. In …show more content…
R. Proffit the dentition and the alveolar process usually compensate for deviations in jaw relationship (Tallgren and solow) but when these compensation becomes impossible, the head posture correlates with the other facial and dental characteristics of the long face syndrome, so called skeletal open bite and these altered postural relationships of the head, jaw and tongue collectively are characteristic for patients with the long face syndrome altered postural relationships of the head, jaw and tongue are characteristic for patients with the long face syndrome (W.R. Proffit et al 1977).
Opdebeeck et al 1978 analysed and compared linear and angular measurements for short face and long face syndrome and concluded that the characteristics of the long face and short face syndrome group can be explained by rotation of the mandible in concert with the movement of hyoid, tongue, pharynx and cervical spine.
(Bibby et al, 1981) proposed new technique in which they introduced the ‘hyoid triangle’ taking Retrognathion (RGn), hyoidale (H) and third cervical vertebra (C3). This triangle allows the assessment of hyoid bone posture in three directions, maybe used to assess normal physiologic position and fuctions of the surrounding anatomy in this area, which may be important in orthodontic and surgical
Brodie points out that as man assumed an upright posture the head had to be balanced on the vertebral column. This is attained by equal anterior and posterior muscle tension relative to the occipital condyles. In …show more content…
R. Proffit the dentition and the alveolar process usually compensate for deviations in jaw relationship (Tallgren and solow) but when these compensation becomes impossible, the head posture correlates with the other facial and dental characteristics of the long face syndrome, so called skeletal open bite and these altered postural relationships of the head, jaw and tongue collectively are characteristic for patients with the long face syndrome altered postural relationships of the head, jaw and tongue are characteristic for patients with the long face syndrome (W.R. Proffit et al 1977).
Opdebeeck et al 1978 analysed and compared linear and angular measurements for short face and long face syndrome and concluded that the characteristics of the long face and short face syndrome group can be explained by rotation of the mandible in concert with the movement of hyoid, tongue, pharynx and cervical spine.
(Bibby et al, 1981) proposed new technique in which they introduced the ‘hyoid triangle’ taking Retrognathion (RGn), hyoidale (H) and third cervical vertebra (C3). This triangle allows the assessment of hyoid bone posture in three directions, maybe used to assess normal physiologic position and fuctions of the surrounding anatomy in this area, which may be important in orthodontic and surgical