《黄帝内经·素问·六节藏象论》
肾，主蛰伏，是封藏真气的根本，为阴精所居之处，其荣华表现在头发，其充养的组织在骨，为阴中之太阴，与冬天的气相通。
肾者，主蛰，封藏之本，精之处也，其华在发，其充在骨，为阴中之少阴，通于冬气。
The kidneys are the master of dormancy, the foundation of the true qi, the dwelling place of the yin essence, its flourishing is reflected in the hair, its nurturing tissues are the bones, it is the greater yin among the yin, and it communicates with the qi of winter.