Location

on the medial lower leg, 3 cun above the prominence of the medial malleolus (ankle bone), in a depression close to the medial crest of the tibia. A cun is the distance between the 2nd and 3rd knuckles, or the distance at the widest part of the thumb.
note; this point is located 1 handbreadth above the prominence of the medial malleolus.

Needling

perpendicular insertion 1.0 to 1.5 inch.

Caution; contraindicated in pregnancy

Moxa is OK

Actions

Tonifies the spleen and stomach
Resolves dampness
Harmonizes the liver and tonifies the kidneys
Regulates menstruation
Induces labour
Harmonizes the lower jiao (intestines)
Regulates urination
Benefits the genitals
Calms the spirit
Invigorates the blood
Activates the channel and alleviates pain

Signs and Symptoms

abdominal pain, borborygmus, abdominal distention, diarrhea, painful menstruation, irregular menstruation, uterine bleeding, morbid leucorrhoea, uterine prolapse, sterility, delayed labour, nocturnal emission, impotence, enuresis (bed wetting), edema, hernia, pain in external genitalia, muscular atrophy, motor impairment, paralysis of lower extremities, headache, dizziness, vertigo, insomnia.

Commentary:

Sanyinjiao is one of the pre-eminent acupuncture points. As its name states it is the meeting point of the three Yin channels of the leg... the Spleen, the Liver and the Kidney channels.

Sanyinjiao is especially useful as a 'balancing' point. That is whatever the disharmony, the action of Sanyinjiao is to bring things back into balance regardless whether the disharmony is an excess or a deficiency. This quality, along with its strong effect on all three Yin organs of the leg gives it an extraordinarily broad range of actions.

While its main action is on the Spleen, it also has a strong effect on both the Liver and the Kidneys

Its main function is to harmonize the Spleen in all its functions. Not only is the Spleen responsible for the transformation and transportation of Qi in the body, it is also responsible for 'keeping things in their place'... referring to organs in their proper place, blood within arteries and veins, etc.

Sanyinjiao then is indicated for undigested food in the stool, diarrhea, abdominal distention and fullness, borborygmus and other such digestive disharmonies.

It is indicated for blood deficiency arising out of Spleen inability to provide adequate Qi to the body, manifesting as palpitations, blurred vision, painful menstruation, and postpartum dizziness,

It is indicated for conditions arising out of the Spleen's failure to 'hold things in their place', such as uterine bleeding, hernia, uterine prolapse etc.,

A deficient Spleen makes the body susceptible to dampness, whether accompanied by heat or cold, manifesting as heaviness of the body, heaviness of the limbs, and especially in the lower jiao manifesting as diarrhea, leucorrhoea.

The three yin channels of the leg all pass through and the genital area. Sanyinjiao is the distal point of choice for virtually any disharmony involving any gynecological disorder, menstruation, conception, leucorrhoea, and the external genitals.

However, because if its ability to induce labour, and expel a dead foetus it is generally contraindicated during an otherwise healthy pregnancy.

Sanyinjiao is an important point in the treatment of any sexual disorder in both women and men including pain and contraction, seminal emission, impotence, and excessive sexual drive.

Most urinary disorders including difficult urination, retention of urine, enuresis (bed wetting), & cloudy urine, can all be treated with Sanyinjiao.

Sanyinjiao's effectiveness is not restricted to the Lower Jiao. It is often indicated for treatment of insomnia. The Spleen's involvement is explained by the fact that the Spleen is responsible for the Transformation and Transportation of Qi. Disharmonies arising out of Qi deficiency, or Qi and Blood deficiency, in other parts of the body can be traced back to the Spleen. An essential part of the treatment for any disharmony diagnosed as a deficiency of Qi or Qi and Blood, would include fortifying the Spleen.

Finally, it is an essential assumption of TCM diagnosis that everything is connected to everything else in the body. At the centre of everything is the Spleen. It is the organ responsible for producing the 'motive force' of the body, Qi. Sanyinjiao is the single most important point for balancing the Spleen, not only regarding its ability to do its job, but in its relationships with other organs.