BL37 (Yinmen, “Gate of Abundance”) is an acupuncture point on the Bladder Meridian. It is located on the posterior midline of the thigh, 6 cun inferior to the center of the transverse gluteal fold (BL36 Chengfu) and 8 cun superior to the popliteal crease (BL40 Weizhong). It activates the channel and alleviates pain, strengthens the lumbar region and legs, resolves local swelling and stagnation.
On the posterior midline of the thigh, 6 cun inferior to the center of the transverse gluteal fold (BL36 Chengfu) and 8 cun superior to the popliteal crease (BL40 Weizhong).
Perpendicular insertion, 1.5 to 2.5 cun. Caution is advised to avoid the sciatic nerve, which lies deep to the biceps femoris muscle.
Activates the channel and alleviates pain, strengthens the lumbar region and legs, resolves local swelling and stagnation.
Low back pain where one cannot bend forward or backward, low back and spine cannot bend forward or backward, low back pain where one can bend forward but not backward, pain in the low back, spine, buttocks, and coccyx from cold, swelling of the outer thigh, low back and spine pain pulling on each other as if dislocated, pain resulting from lifting heavy objects with subsequent stagnation of 'bad blood'.
Yinmen is a primary distal point for treating acute and chronic low back pain, especially sciatica and pain radiating down the posterior leg. Its location directly over the hamstring muscles and sciatic nerve makes it effective for local conditions like hamstring strains and posterior thigh pain. The classical indications emphasize its utility for lumbar pain with severe restriction of movement, particularly difficulty with extension (bending backward), often associated with trauma or strain.
Classical text; the translation was prepared with AI and is not clinical advice.
《類經圖翼》 Lèijīng Túyì — Illustrated Wings to the Classified Canon, Zhang Jiebin, 1624 · 卷七 · 經絡（五） · 足太陽膀胱經穴 · Source: jicheng.tw ↗
殷門 在承扶下六寸，膕上兩筋之間。 刺七分，留七呼，灸三壯。 主治腰脊不可俯仰，惡血流注，外股腫According to this text, BL37 lies 6 cun below Chengfu, between the two tendons above the back of the knee; needle 7 fen, retain 7 breaths, moxa 3 cones. It records use for a lumbar spine unable to bend, flowing stagnant blood, and swelling of the outer thigh.
《神灸經綸》 Shénjiǔ Jīnglún — Principles of Divine Moxibustion, Wu Yiding, 1851 · 卷之二 · 十二經脈起止 · 膀胱經六十三穴分寸 · Source: jicheng.tw ↗
殷門 從承扶下行六寸膕上兩筋之間灸三壯一云在浮郄下二寸又云六寸According to this text, BL37 lies 6 cun down from Chengfu between the two tendons above the back of the knee, with 3 moxa cones; it notes other opinions placing it 2 cun, or 6 cun, below Fuxi.
《針灸甲乙經》 Zhēnjiǔ Jiǎyǐ Jīng — Systematic Classic of Acupuncture & Moxibustion, c. 256–282 · 卷09 · Source: Wikisource ↗
腰痛得俯不得仰，仰則恐仆，得之舉重，惡血歸之，殷門主之The text records that BL37 was used for low back pain allowing bending forward but not backward, with fear of falling when leaning back, arising from lifting heavy loads with stagnant blood settling there.
BL37 is one of 67 points on the Bladder Meridian. Nearby points:
BL37 (Yinmen) is located on the posterior midline of the thigh, 6 cun inferior to the center of the transverse gluteal fold (BL36 Chengfu) and 8 cun superior to the popliteal crease (BL40 Weizhong).
BL37 activates the channel and alleviates pain, strengthens the lumbar region and legs, resolves local swelling and stagnation. Common clinical indications include low back pain where one cannot bend forward or backward, low back and spine cannot bend forward or backward, low back pain where one can bend forward but not backward, pain in the low back, spine, buttocks, and coccyx from cold, swelling of the outer thigh, low back and spine pain pulling on each other as if dislocated, pain resulting from lifting heavy objects with subsequent stagnation of 'bad blood'.
Perpendicular insertion, 1.5 to 2.5 cun. Caution is advised to avoid the sciatic nerve, which lies deep to the biceps femoris muscle. Caution: The Su Wen, as cited in Zhen Jiu Da Cheng, warns against needling this point in autumn. The Zhen Jiu Ju Ying lists it in a song of points forbidden to moxa, though other sources permit it.
BL37 is a point on the Bladder Meridian (Zú Tài Yáng Páng Guāng Jīng).