《金匮真言论》曰∶春气者病在头，（肝之应也。）夏气者病在脏，（心之应也。）秋气者病在
肩背，（肺之应也。）冬气者病在四肢。（四肢气少，寒毒善伤，随所受邪，则为病处。）
夫精者身之本也。故藏于精者，春不病温。（冬则精气伏藏，阳不妄升，故春无温病也。）平旦至日
中，天之阳，阳中之阳也；日中至黄昏，天之阳，阳中之阴也；（日主阳盛，故曰阳中之阳。黄昏
阴盔，故曰阳中之阴。阳气主昼，故平旦至黄昏，皆为天之阳，而中复有阴阳之殊也。）合夜至鸡鸣，天
之阴，阴中之阴
也；鸡鸣至平旦，天之阴，阴中之阳也。（鸡鸣阳气未出，故曰天之阴，平旦阳气已升，故曰阴中之
阳。）故人亦应之。夫言人之阴阳，则外为阳，内为阴。言人身之阴阳，则背为阳，腹为阴。言
人身之脏腑中阴阳，则脏者为阴，腑者为阳，（脏，谓五神脏。腑，谓六化腑。）肝、心、脾、肺、
肾，五脏皆为阴，胆、胃、大肠、小肠、膀胱，三焦，六腑皆为阳。故背为阳，阳中阳，心
也；（心为阳脏，位处上焦，以阳居阳，故为阳中之阳。《灵枢》曰∶心为牡脏。牡，阳也。）
背为阳，阳中之阴，肺也；肺为阴脏，位于上焦，以阳居阴，故谓阴中之阴。《灵枢》曰∶肺
为牝脏。牝，阴也。）腹为阴，阴中之阴，肾也；（肾为阴脏，位处下焦，以阴居阴，故谓阴中
之阴。《灵枢》曰∶肾为牝脏。牝，阴也。）腹为阴，阴中之阳，肝也；（肝为阳脏，位处中焦，以
阳居阴，故谓阴中之阳。《灵枢》曰∶肝为牡脏。牡，阳也。）腹为阴，阴中之至阴，脾也。（脾为
阴脏，位处中焦，以太阴居阴，故谓阴中之至阴。《灵枢》曰∶脾为牝脏，牝，阴也。）此
皆阴阳表里内外雌雄，相输应也，故以应天之阴阳也。（以其气象参合，故能上应于天。）
The *Jingui Zhenyan Lun* (Treatise on the True Sayings of the Golden Cabinet) states: The pathogenic qi of spring affects the head, (this corresponds to the Liver.) The pathogenic qi of summer affects the zang organs, (this corresponds to the Heart.) The pathogenic qi of autumn affects the shoulders and back, (this corresponds to the Lung.) The pathogenic qi of winter affects the four limbs. (Since the four limbs have less qi, cold pathogens easily injure them; depending on where the pathogen is received, that becomes the site of disease.)
Essence (Jing) is the root of the body. Therefore, those who store essence well will not suffer from warm diseases in spring. (In winter, essence is stored and hidden, and yang qi does not rise recklessly, thus there are no warm diseases in spring.) From dawn to noon, this is the yang of heaven, specifically yang within yang; from noon to dusk, this is the yang of heaven, specifically yin within yang. (The sun governs abundant yang, hence it is called yang within yang. At dusk, yin begins to prevail, hence it is called yin within yang. Yang qi governs the day, so from dawn to dusk, all belongs to the yang of heaven, yet within this period, there is a distinction between yin and yang.) From twilight (heye) to cockcrow, this is the yin of heaven, specifically yin within yin; from cockcrow to dawn, this is the yin of heaven, specifically yang within yin. (At cockcrow, yang qi has not yet emerged, hence it is called the yin of heaven; at dawn, yang qi has already risen, hence it is called yang within yin.) Humans also correspond to these patterns.
When speaking of human yin and yang, the exterior is yang and the interior is yin. When speaking of the yin and yang of the human body, the back is yang and the abdomen is yin. When speaking of the yin and yang within the zang-fu organs, the zang organs are yin and the fu organs are yang. (Zang refers to the Five Spirit Zang organs. Fu refers to the Six Transformation Fu organs.) The Liver, Heart, Spleen, Lung, and Kidney, these five zang organs, are all yin. The Gallbladder, Stomach, Large Intestine, Small Intestine, Bladder, and Sanjiao (Triple Burner), these six fu organs, are all yang.
Therefore, the back is yang; among yang, the heart is yang within yang. (The Heart is a yang organ, located in the upper jiao; residing in yang with yang, it is thus called yang within yang. The *Ling Shu* states: The Heart is a male organ [Mu Zang]. Mu means yang.) The back is yang; among yang, the lung is yin within yang. (The Lung is a yin organ, located in the upper jiao; residing in yin while being yang, it is thus called yin within yang. The *Ling Shu* states: The Lung is a female organ [Pin Zang]. Pin means yin.) The abdomen is yin; among yin, the kidney is yin within yin. (The Kidney is a yin organ, located in the lower jiao; residing in yin with yin, it is thus called yin within yin. The *Ling Shu* states: The Kidney is a female organ [Pin Zang]. Pin means yin.) The abdomen is yin; among yin, the liver is yang within yin. (The Liver is a yang organ, located in the middle jiao; residing in yin while being yang, it is thus called yang within yin. The *Ling Shu* states: The Liver is a male organ [Mu Zang]. Mu means yang.) The abdomen is yin; among yin, the spleen is extreme yin within yin. (The Spleen is a yin organ, located in the middle jiao; residing in yin with Taiyin qi, it is thus called extreme yin within yin. The *Ling Shu* states: The Spleen is a female organ [Pin Zang]. Pin means yin.) These are all instances of yin and yang, interior and exterior, inside and outside, male and female mutually corresponding and interacting, thus they correspond to the yin and yang of heaven. (Because their meteorological aspects interconnect, they can correspond upwardly to the yin and yang of heaven.)