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Located at the center of the neck and the pharyngeal column and, thanks to its attachments, tied to the base of the skull, to the mandible, to the tongue, to the larynx, and to the scapular belt, the hyoid bone is intimately related to an extensive tendino-muscular complex. From this strategic position, the hyoid bone participates in all functional and nutritional activities of the oro-facial complex. Heavily involved in the physiology of the pharyngeal column, it appears to enjoy a remarkable stability in relation to its surrounding structures as it participates in the critical process of vertical ontogenetic development. Deceptively simple in its shape and location it is anything but. While it would be easy to scorn it as a vestigial organ of little importance, the hyoid bone is actually an ancient witness of the evolution of the first human vertebrae and a vestige of the 2nd and 3rd brachial arches. Like a toy buffeted by powerful groups of muscles and tendons, the hyoid bone occupies a crossroads position where it is solicited by many vital functions, the most critical of which is respiration. Its functional behavior seems to have evolved considerably over the course of phylogeny. By piecing together the conceptions of many authors, we can conclude that the similarities--and, later, the differences--existing between the human fetus and those of other primates, and, then between young children and young primates, are related to an essentially different status quo, which modifies the delicate equilibrium of the pharyngeal region. In metamorphosing from a sagittal equilibrium to one that is vertical, this very status quo maintains an open respiratory airway during each time frame, continuously permitting the articulation and modulation of sounds, particularly during the vertical period. The hyoid bone is unpaired, in a mid-line position, symmetrical, and located just below the mandible with which it shares, to an astonishing extent, certain morphological characteristics. Its maturation and its ossification occur slowly and late even though it migrates much more rapidly to a vertical position than does the bulk of the cervical complex. True articulations between the body and the horns of the hyoid bone persist for a very long time; and so the junction between the small horns doesn't fully calcify until about the age of 50; and, in spite of its appearance, the hyoid bone is extremely supple, a quality that allows it to make substantial contributions to functional activity. If the hyoid bone itself scarcely moves during normal respiration, modern research attributes an increasing role to it in the maintenance of the equilibrium of the pharyngeal column. It seems to be called upon to respond to a number of demands that it manages to satisfy as it helps to maintain the permeability of the pharyngeal column and thus make respiration possible. In so doing, the hyoid bone adjusts its positioning, and, perhaps most important, its orientation to the physiological requirements imposed by pharyngeal obstruction and mouth breathing. Intimately connected to the larynx, the hyoid bone plays a part in phonation that has long been recognized. Recent studies now also show that the contribution the hyoid bone makes to respiratory equilibrium is far more important than its small size would suggest.

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This study discusses the morphologic evolution of the cranio-facial and cervical bone structures throughout life. A cephalometric study was made on lateral radiographs. The population studied included 84 males and 102 females. Ages ranged from 21 to 101. The cranial structures, superior facial structure, mandible and cervical vertebral column were successively examined. The anteroposterior diameter of the calvarium does not seem to undergo any modification during life. On the other hand, a highly significant increase of the thickness of this structure can be noted. The upper facial structure presents some modification, namely a significant increase of its posterior height. The palatine processus seems to change direction and pivot downwards and forwards. The maxillary sinus does not undergo any changes. The mandible, which is stable in its major axes, shows more malleable sectors which are more especially situated at the level of its body. The study of the cervical vertebral column reveals a loss of overall height, and an increase in the lordosis. The most numerous and most evident morphologic modifications were observed around the age of fifty in both males and females. The fact that these transformations are always commoned and greater in the latter reveals the plausible influence of the menopause. It appears that bone structures of membranous origin are the site of significant modifications compared with structures of endochondral origin, which benefit from a greater stability.

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Although sutures have been identified as being important growth sites of the craniofacial complex, some points are still debated. The aim of our work was to analyze coronal suture response after immobilization in 24 New Zealand White rabbits. This immobilization was induced by an adhesive that bridged the coronal suture under investigation. Contrary to the reports of several authors, our procedure did not promote craniostenosis. The sutural space remains present even if it appears considerably reduced. Our cytometric examination clearly demonstrates that growth reduction localized on the external cortex of the calvaria whereas the internal cortex have a subnormal evolution. These findings favor a different evolving profile of both tables of the calvaria. They also suggest that one should be very careful before considering this procedure, as it may induce craniostenosis.

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We report an osteotomy technique for the maxilla using an iliac graft and simultaneous implantation for correction of atrophic class III dysmorphosis of the maxilla. The advantages and disadvantages of this technique are discussed on the bases of a 3-year experience.

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Ageing of the face is one of the most apparent. Face varies in shape and aspect. The reasons of these modifications are various: skin ageing, lost of teeth, changes in facial skeleton and modifications of the whole facial soft tissues. Soft tissues evolution in mentalis and anterior nasal spin regions was studied on a 206, 21 to 101 years old subjects population. It was shown that in both men and women samples the soft tissues thickness increase in the mentalis region and decrease in that of anterior nasal spin.

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Is the balance of the hyo-lingual musculature very important about mandibular morphology and orientation of mandibular growth? The purpose of this study is to detect the existence of possible reports between hyo-lingual position and mandibular morphogenesis. The selected population is made of fifty children from eight and a half to ten and a half years old, who are thumb sucking and mouth breathing. The means of study are norma lateralis teleradiographs made when facial musculature is at rest position. The statistical analysis implies a descriptive and correlative analysis of 82 variables, and a comparative study with an other sample. In spite of anatomic bonds, it seems to be a relative independence between lingual morphology and orientation of mandibular growth. Perhaps head posture is it a more important mechanism!

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The purpose of the present study based on the comparison of two populations showing a different average of age, was to see the possible action of the tongue on the mandibular morphology. This study included the examination of norma lateralis teleradiographs, while both facial and lingual musculatures were in rest position. If it appears that older subjects show a close correlation between mandibular divergence and lingual height, this relation doesn't take place in younger subjects although they present an earlier mandibular hyperdivergence. May breathing, a function hierarchically of the highest importance be more determinant in lower face organisation than deglutition and lingual equilibrium?

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The purpose of this study is to detect the existence of eventual relations between position and dimensions of tongue and pharynx soft tissues and vertical growth of face. The population is made up of 50 children of 9 to 11 years old with sucking habits and difficulties in breathing. The documents are teleradiographies in norma lateralis made when the patient is in rest position. This study expounds vertical facial characteristics of this population through a statistical descriptive analysis and then through a correlative approach of those characteristics and some soft tissues measurements.

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