ɪn nˈɑːnmæmˈeɪliən sˈɪnɐpsˌɪdz, ðə dʒˈɔː ɪz kəmpˈoʊzd ʌv fˈoːɹ bˈoʊni ˈɛlɪmənts ænd ɹᵻfˈɜːd tʊ æz ɐ kwˈɑːdɹoʊɑːɹtˈɪkjʊlɚ dʒˈɔː bɪkˈʌz ðə dʒˈɔɪnt ɪz bᵻtwˌiːn ðɪ ɑːɹtˈɪkjʊlɚ ænd kwˈɑːdɹeɪt bˈoʊnz.
In non-mammalian synapsids, the jaw is composed of four bony elements and referred to as a quadro-articular jaw because the joint is between the articular and quadrate bones.