The arrangement of the trabecular bone in the vestibular surface of the human fetus mandible. I. A scanning electron microscopy study (1).

The characteristics of trabecular bone in human fetuses at three to six months intra-uterine life were studied in the vestibular surface of the mental and body portions of the mandible. Rounded trabeculae disposed vertically were observed in the alveolar region of the mental portion until 3 months of age. Bundles of collagen fibers were present longitudinally in the alveolar region of the mandibular body: laminar and longitudinal trabeculae lying parallel to the mandible base were seen in the basilar region. In 4 to 6-month old fetuses rounded trabeculae were observed in the alveolar region of the mental portion; in the medium region, the trabeculae were oblique while in the basilar region they were longitudinal and parallel to mandible base. In the alveolar region of the mandibular body, trabeculae with a rounded aspect were seen: in the medium region, they were straight, oblique and longitudinal to the mandible ramus: in the basilar region, the trabeculae were longitudinal and parallel to mandible base. The alveolar foramina exhibit differing diameters and shapes in the mental and body portions: thick bundles of collagen fibers and osteocyte lacunae of varying diameters were present in the bone surface.