As already mentioned in Chap. 27 , in many textbooks, it is roughly stated that the mandible arises as a desmal ossification next to Meckel’s cartilage. However, there are many further cartilaginous structures, which eventually contribute to the formation of the mandible once it is a completed bone. Meckel’s cartilage itself, which first serves as framework for the two lateral bony plates, eventually vanishes almost completely due to resorption and ossification. The only remnants of its existence are parts of the spheno-mandibular ligament and the malleus as its most posterior part. In the anterior region of the mandible, also referred to as the symphyseal region, a number of transient cartilaginous islets have been described. In the posterior part of the mandible, there are also several cartilaginous structures. There are carrot-like cartilaginous cores inside the condylar and the coronoid processes, visible in human fetuses between 50 and 120 mm CRL. In later stages, they are prone to ossification. Also, at the angular process, transient cartilaginous tissue has been described for humans and for several other species. The 3-D reconstructions made it possible to clearly localize the islands of cartilaginous tissue and to distinguish their position from any other cartilaginous structures such as Meckel’s cartilage or its insular decay products. Only those cartilaginous islands within bone, which were located in the course of Meckel’s cartilage—or where it did run in previous stages—may be remains of it.