Back to search result Search again Previous Next ↑

Alternate names: 郄中 xī zhōng, Cleft Center; 血郄 xuè xī, Blood Cleft; 中髎 zhōng xī, Central Cleft; 足太阳所入 zú tài yáng suǒ rù, Entry Point of the Foot Greater Yang

Channel: BL, foot greater yáng (tài yáng) bladder channel

Modern location: An acupoint located on the posterior aspect of the knee, at the midpoint of the popliteal crease.

Classical location: At the pulsating vessel in the center of the popliteal crease. From The Systematic Classic of Acupuncture and Moxibustion (针灸甲乙经 zhēn jiǔ jiǎ yǐ jīng)

Local anatomy: Superficially, the femoropopliteal vein; deeper and medially, the popliteal vein; at the deepest level, the popliteal artery. The posterior femoral cutaneous nerve, the tibial nerve.

Action: Clears the blood and discharges heat; soothes the sinews and frees the network vessels; dispels wind-dampness; disinhibits the lumbus and knees.

Modern indications: Lumbar pain; wilting-impediment (wěi bì) of the lower limbs; abdominal pain; vomiting and diarrhea; inhibited urination; enuresis; cinnabar toxin (dān dú).

Classical indications: Absence of sweating in febrile disease; persistent nosebleed; night sweating; wind-damp loss of locomotive ability; sudden turmoil (cholera) with gripping pain in the heart [region] and abdomen; clove sores (dīng chuāng); welling- and flat-abscesses (yōng jū); aching among the lower teeth; throat disorders.

Needle stimulus: Needling: 0.5‒1.5 cùn perpendicular insertion; bleed with three-edged needle (avoid deep lancing). Moxa: 3‒5 cones; pole 5 min.

Needle sensation: Distension and numbness, sometimes spreading to the soles of the feet.

Point groups: Uniting (hé) (earth) point; command (sì zǒng) point of the back; one of Mǎ Dān-Yáng’s twelve heavenly star points.

Point name meaning:

• 委 wěi: crooked, bent; to bow under a burden
• 中 zhōng: center, central, middle (also zhòng, to strike)

This point is at the center of the crease at the bend of the knee and is thus named Bend Middle.

The functions of BL-40 to clear the blood, drain heat, and treat acute back sprain are best activated by drawing blood from the small veins surrounding the point. Thus, it is sometimes referred to by the alternate name Blood Cleft. See acupoint names: origins, meanings, and translations.

Back to search result Search again Previous Next