Final answer:
The growth of the naso-maxillary complex involves sutural, endochondral, and appositional mechanisms. The facial bones expand through sutural growth and intramembranous ossification, while endochondral ossification contributes to the lengthening of bone from cartilage models. Appositional growth modifies bone shape and thickness over time.
Step-by-step explanation:
The mechanisms of growth of the naso-maxillary complex include sutural growth, which involves the addition of bone at the sutures, the fibrous joints between the bones of the skull. This type of growth is largely responsible for the increase in the size of the face during childhood as the sutures allow the facial bones to expand as the paranasal sinuses enlarge.
Another mechanism is endochondral ossification, which is the process by which cartilage is transformed into bone. This occurs within the cartilage of the nasal septum, contributing to the lengthening of the midface. Lastly, appositional growth also plays a role in the development of the facial skeleton, where new bone tissue is added to the surface of existing bone, allowing for changes in shape and thickness over time.
Both intramembranous and endochondral ossification are pivotal in facial bone development. In intramembranous ossification, which forms the facial bones, mesenchymal cells directly differentiate into bone-forming cells. In contrast, endochondral ossification produces a hyaline cartilage model first, which is then gradually replaced by bone tissue, as seen in the growth of the nasal bone and maxillary bones. These growth mechanisms contribute to the facial changes that occur during the transition from childhood to adulthood.