至陰 : Zhiyin : Reaching Yin

Classifications:

Jing-Well and Metal point
Mother point of the Bladder channel
Exit point to Yongquan Kid-1

Location:

On the dorsal aspect of the little toe, at the junction of lines drawn along the lateral border of the nail and the base of the nail, approximately 0.1 cun from the corner of the nail.

Needling:

Perpendicular or oblique insertion directed proximally 0.1 - 0.2 cun, or prick to bleed

Classical Needling:

"The Taiyang usually has much Blood and little Qi" (Su Wen 素問 ch. 24) implying this channel should normally be bled.
"The foot Taiyang is to be pierced 5 fen deep and remain inserted for seven exhalations" (Ling Shu 靈樞 ch. 12).
"It is needled to a depth of one fen, (the needle) is retained for a duration of five exhalations, and it is moxaed with three cones" (Huangfu Mi 皇甫謐, 3rd Century, Zhenjiu Jiayi Jing 針灸甲乙經).

TCM Actions:

Expels Wind and clears the head and eyes
Turns the foetus and facilitates labour

TCM Indications:

• Vertex headache, occipital headache, heaviness of the head, neck pain, nasal congestion, nosebleed, eye pain, pain of the inner canthus, Superficial Visual Obstruction, deafness and tinnitus, pain of the lateral costal region and chest, agitation of the Heart.
  
• Retention of placenta, malposition of foetus, delayed labour, prolonged or difficult labour.
  
• Difficult urination, painful urinary obstruction, seminal emission, cold Malarial (瘧, Nue) Disorders, wind cold starting from the little toe, absence of sweating, heat in the soles of the feet, cramps, clonic spasm, swelling of the knees.

I Ching Hexagram:

䷻ Jie 節 Limitations

Shared with Zhiyin Bl-67 and balanced by ䷷ (Shenmen He-7 or Xiaohai SI-8).

Hexagram attributions are my own with an explanation given in the glossary.

Neuroanatomy:

Superficial Innervation: Sural nerve (L5 - S2)

Dermatome Segment: S1

Deeper Structures: Sural nerve (L5 - S2)

Martial Applications & Effects of Injury:

See Montaigue, Dim Mak Locations, Taijiworld.com for explanation of effects.

Major Combinations:

• To hasten delivery:
    Zhiyin Bl-67 with Zusanli St-36
    (Anon, nd, Shi Si Jing Yao Xue Zhu Zhi Ge, 十四經要穴主治歌, Song of the Points of the Fourteen Primary Channels).
  
  
• Seminal emission:
    Zhiyin Bl-67 with Ququan Liv-8 and Zhongji Ren-3
    (Wang Zhizhong, 王執中, 1220: Zhen Jiu Zi Sheng Jing, 針灸資生經, Classic of Supporting Life with Acupuncture and Moxibustion).
  
  
• Difficult urination and seminal emission:
    Zhiyin Bl-67 with Zhongji Ren-3, Ligou Liv-5, Chengfu Bl-36 and Lougu Sp-7
    (Wang Zhizhong, 王執中, 1220: Zhen Jiu Zi Sheng Jing, 針灸資生經, Classic of Supporting Life with Acupuncture and Moxibustion).
  
  
• Itching with much pain:
    Zhiyin Bl-67 with Wuyi St-15
    (Gao Wu, 高武, 1529: Bai Zheng Fu, 百症賦, Ode of a Hundred Symptoms).
  
  
• Paralysis of the lower extremity:
    Zhiyin Bl-67 with Yinlingquan Sp-9, Huantiao GB-30, Yangfu GB-38 and Taixi Kid-3
    (Yang Jizhou, 杨继洲, 1601: Zhen Jiu Da Cheng, 針灸大成, Great Compendium of Acupuncture and Moxibustion).
  
  
• Vertex headache:
    Zhiyin Bl-67 with Baihui Du-20 and Houxi SI-3 (Deadman, Al-Khafaji and Baker, 2001, A Manual of Acupuncture).

Notes:

Well known empirical point for turning a malpositioned foetus during labour through the use of moxa (Van der Berg et al, 2008, Effectiveness of acupuncture-type interventions versus expectant management to correct breech presentation: A systematic review).

In five element acupuncture this point is reinforced to tonify Bladder deficiencies.

Ling Shu Ch. 19, on the Four Seasonal Qi, advises selecting the Jing-Well and Ying-Spring openings in winter, piercing deeply and retaining for a while. However, the character for "retain" 留 is a combination of 田 "a field," possibly referring to the idea of waiting for things to grow, and 卯 which is the 4^th Earthly Branch (Mao, Rabbit, ䷡, 5-7 am, Large Intestine) and said to derive from a Shang Dynasty glyph, originally referring to a blood sacrifice (a person or animal cut in half) before coming to mean bloodletting and "pouring out" (Smith, 2011). This might suggest it was actually referring to bleeding these points, and maybe even letting the points bleed for a time rather than retaining the needle.

Cecil-Sterman explains that combining the Shu-Stream and Jing-Well points directed outwards is a method of expelling Pathogens from the Taiyang.

In Maoshan Daoism the character for Jing 井 is used to trap disease, ghosts and demons. It is drawn in the air invoking the "three mountains" mudra (index, middle and ring finger extended) with the bent line continuing in a circle (usually clockwise), or with ash and sprayed on with water held in the mouth, and sometimes on talismans (Read, 2020, FB Post, 1 Sep 2020). This may explain why the Jing-Well points are so often used to expel pathogens.

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

Reference Notes:

Basic information on location, needle depth, TCM actions, indications and combinations is taken from Deadman et al (2001): A Manual of Acupuncture with additional anatomical information researched by reference to Gray's Anatomy (38th Ed., 1995) unless otherwise referenced. Images were found on acupunctureschoolonline.com and can be traced back to Claudia Focks (2008) Atlas of Acupuncture originally. I cannot claim any credit or rights over them. Other sources should be quoted in the text.

For some of the more unusual terms I have created a glossary here