[This is from the upcoming translation of Explanations of Channels and Points, translated by Michael Brown and edited by Allen Tsaur, published by Purple Cloud Press. This work may not reflect the final edition. Part 2 next will include the diseases that BL-13 treats]
BL-13 Fèi Shù – Lung Shu
膀胱經第十三穴肺腧
穴在第三椎下兩旁，相去脊一寸五分。《千金》云：對乳引繩度之。甄權云：以搭手，左取右，右取左，當中指末是穴，正坐取之。
This point is located beside and below the third vetebra, 1 cùn 5 fēn from the spine, on each side. The Qiānjīn states [it is] opposite the breast, draw a string to locate it. The Zhēnquán states put the hand over the shoulder, for left [point] use right [hand], for right [point] use left [hand], spot under the tip of the middle finger is the point, sit upright to locate it.
《甲乙》：鍼三分，留七呼，得氣即泄。甄搏：灸百壯。《明下》：灸三壯。《素》戒云：刺中肺，三日死，其動爲咳。
The Jiǎyǐ states needle 3 fēn, retain for 7 respirations, obtain qì then promptly drain. Zhēn bó states moxa 100 zhuàng. The Míngxià states moxa 3 cones. The Sùwèn warns piercing into the lung, in three days there will be death, and manifest as coughing.[1]
注：五臟六腑皆系於背，乃系於背之挾脊脂絡中，其腧穴，按臟腑之高下而定焉，實臓腑至要之處，爲臓腑之本也。太陽一經，歷主其穴，所謂巨陽者，蓋一身之臓腑無所不統也。
Explanation: the five zàng-viscera and six fǔ-bowels all have connectors on the back, that connect to the fatty network on the back that clasps the spine. As for the [back] transport points, [their locations] are determined by the relative height of the zàng-viscera and fǔ-bowels. They are truly the most crucial places and foundations of the zàng-viscera and fǔ-bowels. The channel of the tàiyáng passes through and governs these points. This is the reason it is called the great yáng, as all the zàng-viscera and fǔ-bowels of the body are governed by it, without exception.
各腧即統其原於挾脊之兩旁，而各腧臟腑之餘，本經背一行之支别者，又再分按其部而主之，故臓腑外受之邪，無不取於本經在背之穴也。
Each back transport [point] precisely controls its origin on the [lateral] side of the paravertebrals, and transports the surplus of its respective zàng-viscera and fǔ-bowels. For the diverging branch of first line of this channel on the back, it also governs based on its location. Thus, when the zàng-viscera and fǔ-bowels externally contract an evil, without exception always select a point of this channel that is on the back.
肺處五臓最高之所，故肺腧首取之，乃系肺之原本處也。仲景曰傷寒太陽與少陽並病，頭項强痛或眩冒，時如结胸，心下痞者，當刺足太陽肺腧、肝腧。
The lung is situated in the highest place of the five zàng-viscera, therefore Fèi Shù (BL-13) is the first to adopt [this category], it also connects place that is the origin and foundation of the lung. Zhòngjǐng says “When there is cold damage of the tàiyáng together with the shǎoyáng, this is dragover disease. There is headache and stiff painful nape, or possibly veiling dizziness, periodically feeling as if there is chest bind, glomus below the heart, one should peirce the foot tàiyáng Fèi Shù (BL-13) and Gān Shù (BL-18)”.[2]
又諸腧穴，皆爲臟腑至要之所，鍼之深斷不可過三分，故古人著戒有中肺、中心、中膈之戒，非真中肺、中心也，謂中其系肺、系心之本也。
For all the back transport points, they are the most crucial places for all the zàng-viscera and fǔ-bowels, thus the depth of needling should certainly not exceed 3 fēn; therefore, the ancients composed warnings against [piercing] into lung, heart, and diaphragm; however, this is not truly [piercing] the lung and the heart, but the foundation of the connector to the lung, and of the connector to the heart.
所謂前邊深似井，言在腹諸穴也，後邊薄似餅，言在背諸穴也，可不慎哉。
It is said that the front [of the body] is deep like a well, that is regarding all the points on the abdomen. The back of the body is thin like a round flat cake. Regarding all the points on the back, [one] cannot carelessly [pierce] them!
[1] From Sùwèn Chapter 52.
[2] This is slightly modified quote from Line 171 of the Shānghán Lùn.