Points Database

: Weizhong : Middle of the Crook

Bl-40 : Foot Taiyang Bladder 40

Classifications:
He-Sea and Earth point

Gao Wu Command point
Ma Dan-yang Heavenly Star point
Doorway to the Earth point
Confluent point of the Bladder and Kidney Divergent channels (Cecil-Sterman, 2012, Advanced Acupuncture)
Opening point of the Bladder Divergent channel (ibid.)
One of the "59 piercings" for clearing Heat in Su Wen Ch. 61

Trigger point (Travell & Simons, 1998, Trigger Point Manual)

Meetings:
Meeting of Bladder with Bladder Divergent and Kidney Divergent

Location:
At the back of the knee, on the popliteal crease, in a depression midway between the tendons of biceps femoris and semitendinosus. Locate with the knee slightly flexed.

Needling:
Perpendicular insertion 1 - 1.5 cun, or prick and bleed the superficial veins.

Warning:
The tibial nerve and popliteal artery and vein lie deep to this point.


TCM Actions:
Benefits the lumbar region and knees
Activates the channel and alleviates pain
Cools the blood
Clears summer-heat and stops vomiting and diarrhoea
Benefits the bladder

TCM Indications:
  • Pain and stiffness of the lumbar spine, heaviness of the lumbar region and buttock, cold sensation of the sacrum, coccyx and thigh, knee pain extending to the big toe, difficulty in flexing and extending the hip and knee joints, contraction of the sinews around the popliteal fossa, weakness of the legs, atrophy disorder and painful obstruction of the lower limb, wind painful obstruction, windstroke, hemiplegia.
  • Injury by summer-heat, febrile disease with absence of sweating, injury by cold with heat of the four limbs, alternating chills and fever, malaria, ceaseless thirst, sudden turmoil disorder with abdominal pain, fullness of the lower abdomen, vomiting and diarrhoea, dysenteric disorder.
  • Enuresis, difficult urination, dark urination, distension and pain of the hypogastrium.
  • Nosebleed, pain of the lower teeth, headache, throat painful obstruction, epilepsy, haemorrhoid pain.
  • Clove sores, erysipelas (cinnabar toxin), eczema, urticaria.

    Neuroanatomy:
    Superficial Innervation: Posterior cutaneous nerve of the thigh (S1 - S3)
    Dermatome Segment: S2
    Deeper Structures: Tibial nerve (L5 - S2)

    Trigger Point Associations:
    Muscle: Plantaris
    Myotome Innervation: Tibial nerve (L5 - S2)
    Pain Referral Pattern: Local to point and to upper calf
    Indications: Pain in the back of the knee and upper calf

    Notes:
    Location of popliteal pulse

    This point is also on the 4th trajectory of the Chong mai relating to structural aspects of the body via the Qiao (Yuen, 2005, The Extraoridinary Vessels).

    This point is unusual in Cecil-Sterman's Bladder Divergent treatment in that it is both the opening and confluent point (Cecil-Sterman, 2012, Advanced Acupuncture).

    The "59 piercings" are named in the Su Wen Ch. 61 and mentioned in Su Wen Ch. 32 for treating Heat diseases. This point along with Yunmen Lu-2, Jianyu LI-15 and Yaoshu Du-2 clear Heat from the four limbs.

    Ling Shu Ch. 6 suggests piercing the He points of the Yang channels if a disease is in the Yang of the Yang realm (e.g. the skin). This would mean using this point, presumably needled at a very superficial level, to treat skin level disorders relating to this channel.

    Combining this with the needling techniques described in Chapter 7 we could suggest using either superficial needling here to influence pathogens in the skin, or leopard spot needling (three needles aimed at letting blood from each side) for pathogens in the Blood.

    Ling Shu Ch. 9, On Ends and Beginnings, advises that in the case of Heat associated with receding Yin Qi the Yang conduit should be pierced once and the Yin conduits twice. Based on other recommendation to use the He-Sea of the Yang conduits (Ch. 19) and the Yuan-Source with the Ying-Spring points (Chs. 6, 19 and 24) to clear Heat from the Zangfu, that would suggest this point, Taixi Kid-3 and Rangu Kid-2 as a protocol to clear Heat in the Kidney/Bladder. Next it advises that in Cold associated with receding Yang Qi the Yang should be pierced twice and the Yin> once but no such obvious protocol is evident for this situation.

    Ling Shu Ch. 19, on the Four Seasonal Qi, advises using the He-Sea points in autumn when diseases are in the Fu organs.

    Ling Shu Ch. 23, On Heat Diseases, recommends letting blood form this point in Wind-Strike with cramps and arching backwards.

    Ling Shu Ch. 26, On Miscellaneous Diseases, advises bleeding this point in case of a nosebleed that does not stop after piercings Wangu SI-4.

    Ling Shu Ch. 71, On Evil Visitors, says that when a depletion evil is in the Kidneys it remains in the hollows of the knees. Yuen's theory of the Divergent meridians suggests that they store pathogens at the major joints, depleting our resources while they do, which would make this a potential point for for the Kidney/Bladder Divergent.

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    Important point for acute and chronic lumbar pain and sciatica. It is traditionally bled if the veins here were dark and engorged (Deadman et al, 2001).

    The same advice is given in Hippocrates' The Nature of Man where the author recommends bleeding the veins at the back of the knee or the outer ankle in cases of pain in the back and loins. The vessels described here, as originating from the back of the head and running externally to the spine, down the legs and to the outer ankle, bears a striking similarity to the foot Taiyang Bladder channel in Chinese medicine.

    He also advises venesection in the popliteal area or the inner ankle for pain the loins and testicles but this appears to relate to Yingu Kid-10.

    This point was also mentioned by Galen along with Sp-5 to be bled in the case of suppression of menses (Brain, 1986, Galen on Bloodletting, p.83). According to him scarification at the ankles was more suitable for those of fair skin, while those of darker skin were more suited to bleeding at the knees. The best procedure was to bleed one leg 3-4 days before menses was supposed to begin, and then bleed the other leg the next day (ibid.: p.93) while on a 'reducing' diet. Conversely Trousseau (1872, Lectures on Clinical Medicine, Vol. V, p.218) recommended bleeding from the arm to bring on menses within the hour.

    This was a popular point for ancient phlebotomy, where the popliteal vein is located. In Greek and Roman times it was indicated for severe pain in the region of the kidneys with numbness of the thigh on the corresponding side (Brain, 1986, Galen on Bloodletting, p.23).

    It was also mentioned for nephritis, inflammatory conditions of the uterus and bladder, disorders of the hip, epileptics and scotomatics (Brain, 1986: p.93-94).

    Hippocrates also mentions this point in relation to urinary symptoms in young people. In Epidemics VI he mentions bleeding the sublingual veins at Jinjin & Yuye effect for and advises using the popliteal veins instead (Ibid.: p.114).

    Medieval phlebotomy point (John de Foxton, 1408: Liber Cosmographiae, maa.cam.ac.uk; Hans von Gersdorff, 1517: Feldtbüch der Wundartzney, www.nlm.nih.gov)

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    In ayurvedic medicine:
    Janu marma point
    Size: 1 angula (cun)
    Structure: Tendon
    Effect of Injury: Disability (vaikalyakar marma)
    (Harish Johari, 1996, Ayurvedic Massage, Sanatan Society; Anupama Bhattacharya, Marma Shastra)

    Lad and Durve (2008) in Marma Points of Ayurveda call this point the posterior Janu point and associate it with Vyana Vayu, Prana Vayu, Apana Vayu, Udana Vayu, Shleshaka Kapha, Kledaka Kapha and Avalambaka Kapha.

    They give the following functions:
    - Benefits the knees
    - Promotes circulation
    - Relieves pain locally
    - Enhances the flow of prana
    - Improves cerebral circulation
    - Relieves respiratory distress

    Another anterior Janu point is located in the centre of the kneecap in the middle of a triangle drawn between Heding and the two Xiyan points.

    In Tibetan medicine:
    Moxa point (AMNH, Tibetan Medical Paintings)

    In Thai massage:
    Acupressure point along the Itha (left) and Pingala (right) sen lines running from the navel Shenque Ren-8 to this point and up the back to the neck and head.
    Indicated for back, leg and knee pain/injury/arthritis and sciatica.
    (Salguero & Roylance, 2011, Encyclopedia of Thai Massage)


    Reference Notes: (click to display)