《黄帝内经·素问·生气通天论》
汗孔的开闭调节失常，寒气就会随之侵入，损伤阳气，以致筋失所养，造成身体俯曲不伸。
开阖不得，寒气从之，乃生大偻。
The opening and closing of the sweat pores is abnormally regulated, so cold energy invades, damaging the yang energy, so that the muscles and tendons do not receive nourishment, which causes the body to become hunched and unable to stretch.