19.The length of the face determined by the distance of separation of jaws. The reference mark are nasospinale and chin point .The distance of these two marks is VD.
临床上,面下部垂直距离的参考志点一般用鼻下点和颏下点,这点分别位于口裂的上、下方。
20.Is different what with the ophidia is - - is unable to cause own lower jaw dislocation to swallow the build big game, their steadily external ear and the small eyelid.