[Development of the mandible and its vascularization in human fetuses in light of morphologic, microangiographic and gnathometric studies].

Studies were carried out on 75 mandibles of human fetuses from the 4 to 9th month of fetal life. There were 31 female and 44 male fetuses. The material came from the Institute of Normal Anatomy--Pomeranian Medical Academy. Investigations consisted in filling the external carotid artery and its branches with Micropag. After filling the arteries, the head of the fetus was isolated and fixed in formalin solution in concentration--1.11 mol/dm3 for the period of 3 weeks. Next the mandibles with articular capsule were excised, soft tissue removed and cut at the site of symphysis. Some of the mandibles were decalcified in the solution of nitric acid in concentration--1.16 mol/dm3 for the period of two weeks. All the mandibles were X-rayed employing Unipan 401 equipped with a micro focus X-ray tube for structural examinations. Radiogram photo copies were equipped with a micro focus X-ray tube for structural examinations. Radiogram photo copies were made by the positive method to obtain additional blow up. The decalcified mandibles were X-rayed again. In order to perform a thorough study of vascularization, the decalcified mandibles were cut into specimens (transverse longitudinal axis) about 500 microns thick, thereafter structural pictures were taken--enlarged 9, 11, 17, 22 and 25 times. The decalcified mandibles were exploited to prepare histological specimens in longitudinal cross-section (along the longitudinal axis of mandible). Further observations referred to the growth of mandibles in the particular age groups. Therefore antropometric measurements were made on X-ray pictures and their results were subjected to statistical analysis (Fig. 1-2). The results of studies (Fig. 3-7) proved that in the radiological photo of human fetuses from 4 to 9th month of fetal life; morphological elements characteristic of extrafetal mandibles were found, (such as: body, angle, ramus, mentum, coronoid process, condylar process, alevoluses and teeth buds). The bone structure of mandible showed trabecular structure with clearly seen borders. The structure of condylar process was of isosceles triangle with different trabecular structure. With age and texture of the triangle shriveled. Vascularization of the body of the mandible with alveolar process derived mainly from the inferior alveolar artery. The condylar process was supplied with rich vascular rete derived from arteries of temporomandibular joint. The coronoid process was vascularized by the adjacent arteries. The condylar process stroma formed cartilaginous model surrounded by trabeculae osseae cuff resembled, by the look and structure, the epiphysis of long bones. The analysis of measurement of the fetal mandibles proved that both halves of the fetal mandible revealed statistic identity. The comparison of the results of mandible measurement in both sexes did not show any significant differences. The mandible parameters presented slow, successive and constant growth month after month, and the greatest dynamics of growth in all mandible parameters was present, however, in the 7th month of fetal life a growth inhibition was observed. The gonial angle was constant, its mean value -148 degrees.