Classica Sinica Medica

正偃

zhèng yǎn

Lying flat · zheng yan

Also rendered: orthopnea (The modern clinical term, but it imports a cardiopulmonary frame) · flat posture (Describes the position and loses the verb)

Pathology

Reviewed · 2026-09

At a glance

Pinyin
zhèng yǎn
Simplified
正偃
Literal
正 zhèng, straight, squarely; 偃 yǎn, to lie supine. To lie flat on the back. It sounds like a posture and is used as a test: in wind water the person cannot do it, and doing it brings on coughing, then worse coughing once startlement is added. The chapter treats the inability to lie flat as a sign with a mechanism rather than as a discomfort.
Shuowen
《說文解字》：偃，僵也，从人匽聲——仰臥也。**「偃」讀 yǎn，本篇六見，是本篇用字之最頻者之一**；**「正」讀 zhèng，本篇六見**。「不」讀 bù；「能」讀 néng；「者」讀 zhě；「胃」讀 wèi；「中」讀 zhōng；「和」讀 hé；「也」讀 yě；「則」讀 zé；「欬」讀 kài；「甚」讀 shèn；「上」讀 shàng；「迫」讀 pò；「肺」讀 fèi；「卧」讀 wò；「得」讀 dé；「出」讀 chū；「清」讀 qīng；「水」讀 shuǐ；「驚」讀 jīng。**「正偃」在本篇凡四見，皆作診法之用**：「不能正偃」一、「正偃則欬」二、「卧不得正偃」三、「正偃則欬出清水也」四——**一語而三復，本篇以之驗水氣之上迫**，與「目下腫」之驗水氣在下者，上下對舉。舊注或以「偃」為臥而不別正與側，然本篇既曰「正偃」，則側臥不在其內明矣。

In brief

Lying flat on the back — in this chapter a test rather than a posture. The person with wind water cannot do it; doing it brings on coughing because the water qi presses upward on the lung, and brings up clear water with the cough. The chapter pairs it with the swelling below the eyes: one sign above, one below, both read as water.

Senses in the classical corpus

1
A posture used as a test 不能正偃，正偃則欬
不能仰臥，仰臥則欬
不能正偃，正偃則欬 — Suwen 33
2
Why it cannot be done 不能正偃者，胃中不和也
胃不和故不得仰臥
不能正偃者，胃中不和也 — Suwen 33
3
Why lying flat worsens the cough 正偃則欬甚，上迫肺也
水氣上迫於肺
上迫肺也 — Suwen 33
4
At night 卧不得正偃，正偃則欬出清水也
臥時不得仰臥，仰則欬出清水
卧不得正偃 — Suwen 33
5
With startlement 諸水病者，故不得卧，卧則驚，驚則欬甚也
臥則驚，驚則欬甚
卧則驚，驚則欬甚也 — Suwen 33
6
The sign above, paired with the one below 微腫先見於目下也
目下之腫與不能正偃，一上一下
微腫先見於目下也 — Suwen 33

Occurrences in the classics

Passages where the term does real work, with the original, pinyin and English on the same line.

Display
1 passages
素問·評熱病論 Suwen 33 · 評熱病論 Read in context →
不能正偃者，胃中不和也。正偃則欬甚，上迫肺也。 不能正偃者，胃中不和也。正偃则咳甚，上迫肺也。
Bù néng zhèng yǎn zhě, wèi zhōng bù hé yě.Zhèng yǎn zé kài shèn, shàng pò fèi yě.
Inability to lie flat: disharmony within the stomach. Lying flat makes the cough worse, because the qi presses upward on the lung.
「正偃」之診。「不」讀 bù；「能」讀 néng；「正」讀 zhèng；「偃」讀 yǎn；「者」讀 zhě；「胃」讀 wèi；「中」讀 zhōng；「和」讀 hé；「也」讀 yě；「則」讀 zé；「欬」讀 kài；「甚」讀 shèn；「上」讀 shàng；「迫」讀 pò；「肺」讀 fèi。**此二句是本篇「隨證釋因」之式**：先舉其證（不能正偃、正偃則欬甚），次斷其因（胃中不和、上迫肺也），與上文「小便黃者，少腹中有熱也」同一句法。**本篇自「邪之所湊」以下，凡十一節皆用此式**，是《素問》釋證之定格。

Compounds built on this term

正偃
zhèng yǎn
lying flat
本篇六見，皆作診法
不能正偃
bù néng zhèng yǎn
unable to lie flat
風水之主證之一
不得卧
bù dé wò
unable to lie down
諸水病者之所同
欬出清水
kài chū qīng shuǐ
coughing up clear water
正偃則見，水氣之徵

How it has been translated

Every rendering below is a decision about which reader is being addressed. There is no neutral option.

Wiseman & Fenglying flatThey keep it plain, since 正偃 in the text is a thing a person either can or cannot do.
Unschuldto lie straightUnschuld keeps 正 as 'straight', which catches the squareness of the posture but sounds odd in English.
This sitelying flatWe use the plain phrase and let the context do the work: in this chapter lying flat is a test the body fails, and the failure is the sign.

Entry status

Review pending — who reviews this?

2026-09

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