In the embryonic jaw, soft tissues, teeth and bone are all developing together without external stresses such as chewing and talking, whereas the adult jaw is a hard, busy place.

• 在胚胎的颌部，软组织、牙齿与骨头是在没有外来压力（如咀嚼与说话）的状况下共同发育，但成年的颌却是一个坚硬而繁忙的部位。