Croissance et morphogénèse postnatales de la mandibule du vison (Mustela vison Schreiber): données sur la dynamique et l'interprétation fonctionnelle des dépôts osseux mandibulaires

Abstract

The postnatal growth and morphogenesis of the mink (Mustela vison Schreiber) mandible are described using 10 specimens of known age, the skeletons of which were labelled in vivo by fluorescein and alizarin. Growth is very active in all mandibular regions during the first 2 months of life. It slows down during the 3rd month. During the 4th month, the whole mandible undergoes resorption, the intensity of which varies locally. Growth resumes during or some time before the 9th month with a deposit of parallel bone fibres in some mandibular regions only. This deposit is still active but goes on at a very low rate in old animals. The structural organization of mandibular bone varies in time and space and the relationships between the structure of bone and its growth rate is clarified. The overall modalities of osteogenesis meet the geometrical requirements of mandibular growth and are obviously a transcription of a specific pattern. They probably integrate, as well, epigenetic factors related to the local mechanical conditions of manducation. The influence of these factors on osteogenesis disturbs the deposit of annual growth lines in periosteal bone, weakening the fundamental hypothesis of the skelettochronology. Thus, the conditions for which this technique should be used are discussed.