Sanyinjiao SP-6 location
SP-6

Sanyinjiao SP-6

Three Yin Intersection · 三阴交 · Sān Yīn Jiāo
Spleen Meridian

Safety Warnings

  • Contraindicated during pregnancy

Needle Depth

1.0–1.5 cun

Needle Angle

90° (Perpendicular)

Body Area

Lower Leg — Medial

Location

3 cun directly above the tip of the medial malleolus, on the posterior border of the tibia, on the line drawn from the medial malleolus to Yinlingquan SP-9.

Previous on channel

Shangqiu SP-5

Next on channel

Lougu SP-7

Main Actions

  • Tonifies the Spleen and Stomach
  • Resolves Dampness and benefits urination
  • Removes Liver Qi Stagnation
  • Tonifies Kidney Qi
  • Calms the Mind
  • Eliminates Blood Stagnation
  • Cools Blood
  • Nourishes Blood and Yin
  • Regulates the Uterus and menstruation

Commentary

Sanyinjiao SP-6 is the most important one of all points, with various of functions. 

Most importantly, it strongly tonifies the Spleen and Stomach against all types of Deficiency patterns of these two Organs, characterized by chronic fatigue, loose stools, poor appetite and abdominal pain. These two Organs supply Food Essence, Blood and Qi to all parts of the body. Thus SP-6 has a powerful effect in tonifying Qi and Blood, especially in the Middle Burner. 

The Spleen rules the transformation and transportation of the Body Fluids. Thus the malfunctioning Spleen gives rise to Dampness. SP-6 is one of the most important points for resolving Dampness in the Lower Burner, especially when the Pernicious Factor is combined with Heat or Coldness. Typical manifestations include vaginal discharge, mucus in the stools, abdominal pain and scrotum or vagina itchiness. 

On top of that, many urination difficulties are caused by obstructed Dampness in the Lower Burner, such as painful and turbid urination or retention of urine. SP-6 is able to remove this obstruction and eases pain. 

Furthermore, it removes Blood Stagnation in Lower Burner, such as the Uterus and Intestines. Therefore, it treats symptoms such as irregular menstruation, infertility, excessive uterine bleeding, clotted dark-colored blood, painful periods or bloody stools. In fact, Sanyinjiao SP-6 is one of the most important point in treating any gynecological diseases, as it regulates the Uterus. 

It cools the Blood as well. The Blood Heat can be an Exterior Pernicious Factor invading the Blood Level of the Four Level Theory or Interior Heat that cause various skin issues. 

As its name 'Three Yin Intersection' indicate, Sanyinjiao SP-6 is the crossing point of the Spleen, Liver and Kidney Channel. Therefore, it is able to treat disharmonies of these three Leg Yin Channels. Most importantly, it removes Liver Qi Stagnation, especially in the Lower Burner, characterized by symptoms such as abdominal pain and distension, constipation with small bitty stools and painful periods.

Secondly, it nourishes Yin of the three Yin Channels. Kidney Yin Deficiency is the most prominent one, with typical manifestations such as dizziness, tinnitus, night sweating, feeling of heat, dry mouth and etc. Blood is part of Yin, thus SP-6 nourishes Blood as well, especially when it is needled together with Zusanli ST-36. 

By promoting the Liver Qi circulation and nourishing Blood and Yin, SP-6 calm the Mind as well, so as to ease irritability and insomnia. When the Spleen fails to create sufficient Blood to the Heart and leads to Heart Blood Deficient, the Mind loses its residence and floats at night, thus the symptoms as insomnia or dream disturbed sleeps. 

Classical Sources

Zhenjiu Jiayi Jing (針灸甲乙經 - The Systematic Classic of Acupuncture and Moxibustion): "Sanyinjiao is located 3 cun above the medial malleolus, in the depression posterior to the tibia, at the meeting of the Foot Taiyin, Jueyin, and Shaoyin. Needle 3 fen, retain for 7 breaths, moxa 3 cones." This text first records SP-6 and establishes it as the crossing point of the three leg Yin channels.

Tongren Shuxue Zhenjiu Tujing (銅人腧穴針灸圖經 - Illustrated Manual of Acupoints on the Bronze Figure): Records the famous case where Prince Tai of Song diagnosed a pregnant woman as carrying one girl, but physician Xu Wenbo diagnosed twins (one boy, one girl). "Reduce at Sanyinjiao, supplement at Hegu of Hand Yangming, and the birth will follow the needle." This established the point's contraindication during pregnancy.

Baizhen Fu (百症賦 - Ode of One Hundred Symptoms): "Needle Sanyin[jiao] with Qihai, specially governs chronic seminal emission and leukorrhea."

Qianjin Yaofang (千金要方 - Essential Prescriptions Worth a Thousand Gold): "For women's leukorrhea with red or white discharge and bleeding, moxa 50 cones at Foot Taiyin, the point 3 cun above the medial malleolus called Sanyinjiao."

How to Locate

Find the tip of the medial malleolus and measure 3 cun superiorly. Locate Sanyinjiao SP-6 in a depression at the posterior border of the tibia medial crest. Sanyinjiao SP-6 is often sensitive to pressure. This feature can be used as reference to identify the point.

Caution

STRICTLY CONTRAINDICATED during pregnancy - strong stimulation can induce uterine contractions and may cause miscarriage or premature labor. This point has a powerful descending action. Only use near term for labor induction under supervision. The great saphenous vein runs nearby; needle carefully to avoid vessel puncture. The tibial nerve lies in the deep layer posteriorly; excessive depth may cause nerve irritation. Point is often naturally sensitive to pressure.

Needle Angle

90° (Perpendicular)

Depth Category

Medium

Standard Depth

1.0–1.5 cun

Needling Directions

Vertically or obliquely 1–2 cun. Caution: Contraindicated during pregnancy, particularly with reducing needle techniques, exception: to promote labor.

Expected Deqi Sensation

Soreness, distension, and heaviness radiating up and down the medial aspect of the leg. De qi may propagate toward the ankle or knee. Some patients report a spreading warmth in the lower abdomen. The point is often sensitive to pressure, which can be used to confirm correct location.

Moxibustion

Particularly Recommended

Duration: 5–15 minutes

Cupping

Questionable

Bloodletting

Recommended

Gua Sha

Recommended

Command Point

Commands region:

Lower Limb

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