SP-09 (Yin Ling Quan) Yin Mound Spring

What does SP-09 Yin Ling Quan do?

Yin Ling Quan SP-09 is the He-Sea and Water point of the Spleen channel, and it is the principal point in Chinese medicine for draining dampness. That one classification organises the whole record. The Spleen is held to govern the transformation and movement of fluids; when that fails, fluid accumulates as "dampness" — heaviness, swelling, discharge, turbid urine, loose stools, a full and sluggish abdomen. SP-09 is the point on the Spleen channel where the literature directs that accumulation to be moved and drained.

• Regulates the Spleen and resolves dampness — the headline recorded action, and the one that puts SP-09 into more damp-clearing prescriptions than any other single point.
• Opens and moves the water passages — the traditional term for the routes by which fluids are conducted through the body and out of it. This is the action behind its use in oedema, in difficult or scanty urination, and in abdominal fullness from fluid.
• Benefits the lower jiao — where dampness most readily settles: turbid or painful urination, vaginal discharge, genital itching and damp-heat in the pelvis.
• Clears damp-heat — dampness combined with heat, the pattern behind burning urination, jaundice and hot, swollen joints in the traditional framework. SP-09 is used for the damp component of that pair.
• Acts locally on the knee — the point sits at the inner knee, and pain and swelling of the knee are in its recorded indications; the swollen, heavy, damp-type knee is the one it fits best, which is the local expression of the same action.

Two things this point is not. It is not the point for tonifying the Spleen's qi — that is Tai Bai SP-03, the Yuan-Source point, or Zu San Li ST-36. And it is not primarily a blood or gynaecological point — that is San Yin Jiao SP-06 and Xue Hai SP-10, its neighbours on the same channel. SP-09 is specifically the draining one, and the distinction matters because dampness and deficiency often appear together and call for different points.

Source: Sacred Lotus sources & references (recorded actions and the He-Sea & Water classification); Deadman & Al-Khafaji, A Manual of Acupuncture, p. 194; Chinese Acupuncture & Moxibustion, pp. 159–160; cross-referenced against multiple online sources.

What is SP-09 Yin Ling Quan used for?

Yin Ling Quan SP-09 is used wherever the traditional diagnosis is dampness — in the abdomen, in the urinary system, in the lower burner or in the knee it lies beside. The indications below are those recorded in the standard reference literature and describe traditional use, not proven treatment.

• Abdominal pain and distension
• Oedema (fluid swelling), including of the legs
• Difficult, scanty or painful urination (dysuria)
• Retention of urine
• Enuresis (bed-wetting)
• Incontinence of urine
• Diarrhoea
• Dysentery
• Jaundice
• Leucorrhoea and genital itching attributed to damp-heat
• Pain in the external genitalia
• Dysmenorrhoea (painful periods)
• Pain and swelling of the knee
• Heaviness of the body and of the limbs

Source: Sacred Lotus sources & references (existing indication record); Deadman & Al-Khafaji, A Manual of Acupuncture, p. 194; Chinese Acupuncture & Moxibustion, pp. 159–160.

How is SP-09 Yin Ling Quan used in practice?

Yin Ling Quan lies on the inside of the leg just below the knee, in the hollow formed where the shin bone flares out into its inner knuckle and the shaft runs down behind it — a depression that can be found by running a finger up the inner edge of the shin until it stops against bone. Sacred Lotus sources & references record the location against both standard references; the practical point is that it is a bony hollow, not a muscular one, and it is usually distinctly tender when dampness is part of the picture. It is used bilaterally and it is used, above all, as the damp-draining component of a prescription.

• With San Yin Jiao SP-06. The two most-used points on the Spleen channel, on the same inner leg. SP-06 is the crossing point of the Spleen, Liver and Kidney channels and the broad gynaecological point; SP-09 is the specific damp-draining one. Together they are the standard Spleen-channel pair for damp accumulation with menstrual or urinary involvement.
• With Feng Long ST-40 — the great phlegm-resolving point. Dampness that has thickened into phlegm is treated with both: SP-09 for the damp, ST-40 for the phlegm. This pairing appears on the Zhong Wan REN-12 record in this library as the standard phlegm-and-damp combination for the middle burner.
• With Zhong Wan REN-12 and Zu San Li ST-36 — where the middle burner is failing to transform fluids in the first place, so that the draining point is supported by points that strengthen the transformation.
• For urinary difficulty and damp-heat below — with Zhong Ji REN-03, the Front-Mu point of the Bladder, and with Pang Guang Shu BL-28. SP-09 supplies the damp-draining action from the leg while the abdominal and back points act locally.
• For oedema — with Shui Fen REN-09, the point on the abdomen whose name means "Water Divide", and with ST-36.
• For the knee itself — with Yang Ling Quan GB-34 on the opposite side of the same knee. The two are sometimes needled from one side toward the other, which is possible precisely because they face each other across the leg.
• Method. Moxibustion is recorded as applicable. In damp-heat presentations the reference literature favours needling with draining technique rather than moxa, since warming methods are not what a heat pattern calls for; in cold-damp presentations moxibustion is used.

Source: Sacred Lotus sources & references (recorded actions, location references and the point records cross-referenced above); Deadman & Al-Khafaji, A Manual of Acupuncture, p. 194; Chinese Acupuncture & Moxibustion, pp. 159–160; cross-referenced against multiple online sources.

Where is SP-09 located?

• A Manual of Acupuncture (p. 194): On the medial side of the lower leg, in a depression in the angle formed by the medial condyle of the tibia and the posterior border of the tibia.
• Chinese Acupuncture and Moxibustion (p. 159-160): On the lower border of the medial condyle of the tibia, in the depression posterior and inferior to the medial condyle of the tibia.

How is SP-09 Yin Ling Quan needled, and what cautions are recorded?

Reference fact: SP-09 is a point of the lower leg with no organ, body cavity or major vessel beneath it, and it carries none of the special cautions that attach to the chest, abdomen or sacrum. Sacred Lotus sources & references record perpendicular insertion of 0.5 to 1.0 inch, with moxibustion applicable. The figures below record what the textbooks document as neutral reference data. They are not instruction, and this page does not teach technique.

The angle and depth the texts record

• Sacred Lotus sources & references record perpendicular insertion of 0.5 to 1.0 inch, with moxibustion applicable.
• Deadman & Al-Khafaji (p. 194) and Chinese Acupuncture & Moxibustion (pp. 159–160) record perpendicular insertion at the same site in a comparable range; oblique insertion directed downward along the back edge of the shin bone is also recorded, and insertion angled toward Yang Ling Quan GB-34 on the outer side of the leg is described in the reference literature for knee disorders.
• Moxibustion is recorded as applicable, with the caveat noted above that warming methods suit cold-damp rather than damp-heat presentations.

The local anatomy, stated plainly

The point lies in the angle between the inner knuckle of the shin bone and the back edge of its shaft, at the front border of the calf muscles. The great saphenous vein runs up the inner side of the leg in this region and the saphenous nerve accompanies it, which is why bruising and a transient sharp or radiating sensation are the ordinarily documented occurrences here. The bone itself lies immediately in front of the needle and limits how far it can travel forward. There is no body cavity behind this point, and no pneumothorax or visceral-injury concern of the kind that governs the thoracic and abdominal points.

Pregnancy

SP-09 is not among the points the classical literature lists as contraindicated in pregnancy. That is worth stating explicitly, because its channel neighbour San Yin Jiao SP-06 is — SP-06 with He Gu LI-04 is the classical labour-expediting pair, and both carry the contraindication in the standard texts and on their records in this library. The two points are three cun apart on the same inner leg, on the same channel, and are constantly used together; a reader who assumes the caution travels along the channel would be wrong in one direction and dangerously casual in the other. The caution belongs to SP-06, not to SP-09.

Risk in proportion

A meta-analysis of prospective clinical studies estimated serious acupuncture-related adverse events at approximately 1 per 10,000 patients, with about half of all recorded events being bleeding, pain or flare at the needle site (Bäumler P et al., BMJ Open 2021;11:e045961, PMID 34489268). A systematic review of the Chinese case-report literature from 1956 to 2010 identified 1,038 adverse-event cases across 167 articles and attributed the serious ones chiefly to improper technique (He W et al., J Altern Complement Med 2012;18(10):892–901, PMID 22967282). The points of the lower leg are not among those that feature in that literature.

Source: Sacred Lotus sources & references (existing needling record); Deadman & Al-Khafaji, A Manual of Acupuncture, p. 194; Chinese Acupuncture & Moxibustion, pp. 159–160; PMID 34489268; PMID 22967282 — each verified resolvable and checked for retraction status before citation.

What does the name Yin Ling Quan mean?

Yin Ling Quan means "Yin Mound Spring" — yin for the inner, yin aspect of the leg, ling for a mound or hill, and quan for a spring or well. The mound is the inner knuckle of the shin bone, the rounded prominence just below the knee on the inside of the leg; the spring is the hollow behind and below it, where the point sits. The name is a description of how to find it.

How is SP-09 different from GB-34 Yang Ling Quan?

These two are the most-confused pair of names in the point nomenclature, and the confusion is designed in. Yin Ling Quan and Yang Ling Quan are deliberate mirrors: the same three characters, differing only in the first, describing the same feature — a mound with a spring beside it — on opposite sides of the same knee. Yin Ling Quan SP-09 sits by the inner knuckle of the shin bone; Yang Ling Quan GB-34 sits by the head of the outer leg bone, the fibula. They face each other across the leg and can be needled from one toward the other.

Beyond the names they have very little in common, and knowing which is which is the practical point:

• SP-09 Yin Ling Quan — He-Sea and Water point of the Spleen channel. Its business is fluids: draining dampness, opening the water passages, urinary difficulty, oedema, diarrhoea, discharge.
• GB-34 Yang Ling Quan — He-Sea and Earth point of the Gall Bladder channel, and the Hui-Meeting point of the sinews. Its business is soft tissue: tendons, ligaments and fascia, anywhere in the body, plus the Liver and Gall Bladder territory.

The rule of thumb that follows: fluid problems go to the yin side, sinew problems to the yang side. Both points are held in this library and each has its own record.

Why does the He-Sea point classification matter at SP-09?

The five-shu points run from the tips of the fingers and toes up to the elbow and knee, and the classical image is of a stream growing into a river and finally into a sea. The He-Sea point is the last and deepest of the five, where the channel qi is said to enter inward and join the body proper — which is why the He-Sea points are the ones the classics associate with disorders of the interior and of the organ itself rather than of the channel's surface. There are twelve, one per channel, and Sacred Lotus sources & references hold the complete set: LU-05 Chi Ze, LI-11 Qu Chi, ST-36 Zu San Li, SP-09 Yin Ling Quan, HT-03 Shao Hai, SI-08 Xiao Hai, BL-40 Wei Zhong, KI-10 Yin Gu, P-03 Qu Ze, SJ-10 Tian Jing, GB-34 Yang Ling Quan and LIV-08 Qu Quan.

The second half of the classification is the five-phase assignment. On a yin channel the He-Sea point is also the Water point, and SP-09 is recorded here as He-Sea and Water point of the Spleen. That doubling is the tidiest correspondence in the whole system: the Water point of the channel that governs fluid transformation is also the point most used to drain fluid. The four other yin-channel He-Sea points are Water points too — LU-05, HT-03, KI-10, P-03 and LIV-08 all carry the same pairing in the records held here — but only at SP-09 does the organ's own function line up with the phase so exactly.

Is there research on SP-09 Yin Ling Quan?

Very little, and none of it clinical in any usable sense. That is worth stating plainly rather than dressed up. A search of the published literature found no randomised controlled trial of SP-09 as an isolated intervention in humans. The point appears constantly inside multi-point protocols — knee osteoarthritis, obesity, oedema, urinary disorders, chronic pelvic pain — and those results describe the protocol, not the point, and are not offered here as evidence for it.

What does exist is a handful of small physiological and animal studies:

• Organ blood flow, in rats. Eighteen rats were randomised to sham electroacupuncture, 2 Hz electroacupuncture at bilateral Yinlingquan SP-09, or 2 Hz at bilateral Ququan LR-08, with laser Doppler measurement of perfusion in the spleen and liver. Stimulation at SP-09 increased perfusion in the spleen but not the liver; stimulation at LR-08 increased perfusion in the liver but not the spleen; sham did neither (Am J Chin Med 2012;40(1):75–84, PMID 22298449). It is a small animal study, and the anatomical spleen is not the Chinese medical Spleen — but it is a rare test of point-to-organ specificity in which two He-Sea points of two different channels behaved differently from each other.
• Bladder function, in rabbits. Forty-eight rabbits with experimentally induced acute urinary retention received electroacupuncture at BL-40, SP-06 or SP-09. All three raised intravesical pressure and bladder ATP content relative to the untreated model, with BL-40 the strongest on ATP and no significant difference between SP-06 and SP-09; needling at a non-acupoint raised pressure but not ATP (Zhen Ci Yan Jiu 2012;37(4):291–5, PMID 23140050). Preclinical, and it does not transfer to clinical practice.
• Motor behaviour, in gerbils. A study of 36 gerbils after global cerebral ischaemia applied acupuncture or electroacupuncture at ST-36 and SP-09 and reported that manual acupuncture normalised locomotor behaviour while electroacupuncture did not (Med Acupunct 2023;35(6):327–333, PMID 38162554). Animal work, and SP-09 was not tested separately from ST-36.
• Gout, uncontrolled. A short clinical report described 52 patients with gout treated by acupuncture at Yinlingquan SP-09 and Taichong LR-03 with bloodletting (Zhongguo Zhen Jiu 2013;33(6):526, PMID 23967642). A single-page uncontrolled case series is not evidence of effect; it is recorded here only because it is one of the very few reports in which SP-09 is a named principal point.

The honest summary is that SP-09's standing rests on its classification and on long recorded clinical use, not on modern evidence. This is the ordinary situation for individual acupuncture points, and it is a more useful thing to tell a reader than a list of protocol trials that mention the point in passing.

How does Yin Ling Quan compare with the points near it?

San Yin Jiao SP-06, three cun above the inner ankle bone on the same channel, is the broad gynaecological and three-channel point where SP-09 is the specific damp-draining one — and unlike SP-09 it is contraindicated in pregnancy. Di Ji SP-08, the Xi-Cleft point of the Spleen, sits between them and is the acute-pain choice for severe period pain. Xue Hai SP-10, just above the knee on the same channel, is the blood point of the group, used for skin conditions and menstrual irregularity. Tai Bai SP-03 on the foot is the Yuan-Source point and the tonification choice when the Spleen is weak rather than waterlogged; Gong Sun SP-04 is its Luo-Connecting point and the Confluent point of the Penetrating Vessel. On the other side of the same knee, Yang Ling Quan GB-34 is the named mirror discussed above. Away from the channel, Feng Long ST-40 is the phlegm point that SP-09 is most often paired with, and Shui Fen REN-09 is the abdominal water point. All are held in this library.

Source: Sacred Lotus sources & references (name, He-Sea & Water classification, the complete He-Sea set and the point records cross-referenced above); Deadman & Al-Khafaji, A Manual of Acupuncture, p. 194; Chinese Acupuncture & Moxibustion, pp. 159–160; PubMed PMID 22298449, 23140050, 38162554, 23967642, each verified resolvable and checked as not retracted; cross-referenced against multiple online sources.