Background: The development of the mandible is closely related to Meckel's cartilage, mandibular division of trigeminal nerve and muscles of mastication.
Objectives: The aim of the study was to investigate the muscular attachments to the developing mandible during prenatal life.
Material and methods: The observations were carried out on serial sections stained according to various histological methods.
Results: At stage 16, the rod shaped Meckel's cartilage followed the general curvature of mandibular process from the otic capsule to the future symphysis menti. The stylohyoid and styloglossus muscles were visible in close relation to the ventral end of Meckel's cartilage. On the medial surface of the cartilage, the mylohyoid muscle, as well as the genioglossus and geniohyoid muscles were visible. At stage 18 the muscles established their temporary attachments to Meckel's cartilage. At the same time, near the posterior end of Meckel's cartilage the primordia of articular disc and pterygoid muscle developed. The primordium of masseter muscle was observed in close relation to the angular portion of Meckel's cartilage at stages 19 and 20. Observations on the developing coronoid process showed the attachment of the lateral pterygoid muscle to Meckel's cartilage at stage 21.
Conclusions: The muscles were connected to Meckel's cartilage by the end of 10th week of development, and after that they moved onto the developing mandible. The observations appear to confirm the hypothesis stating that the muscles attached to the Meckel's cartilage indeed influence the mandibular movements, resulting in a premature dislocation of the mandible.