A few observations about Meckel's cartilage in the human.
In the human embryo, fusion of Meckel's cartilages takes place during mandibular development. It seems to be independent of the endochondral ossification with respect to the developmental sequence.
D002356:Cartilage / Q000196:embryology; D004622:Embryo, Mammalian; D006801:Humans; D008334:Mandible / Q000196:embryology*; D010012:Osteogenesis; D013997:Time Factors