1. What are Collaterals? Collaterals are small branches that diverge from the meridians, forming a vast network system throughout the body. The term first appeared in the Huangdi Neijing, where it is mentioned in Ling Shu: Mai Du: “The meridians are internal, while those that branch out and run horizontally are collaterals; the branches of collaterals are called ‘Sun’.” The concept of collaterals is composed of two parts: “Mai” (脉) refers to the dual nature of blood vessels and meridians, while “Luo” (络) emphasizes its network structure and connecting function.
2. Composition and Distribution of Collaterals:
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Composition:
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Fifteen Collaterals: This includes the twelve primary meridians (each of the three yin and three yang of the hands and feet has one collateral), as well as the divergences of the Ren (任脉) and Du (督脉) meridians, and the large collateral of the Spleen.
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Sun Collaterals: These are finer branches that further diverge from the collaterals, numerous and widely distributed, responsible for further distributing Qi and blood to the organs and tissues throughout the body.
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Floating Collaterals: These are small branches that float on the surface of the skin within the Sun collaterals, visible to the naked eye, often used for diagnosis and treatment.
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Distribution:
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After diverging from the meridians, collaterals progressively refine into a three-dimensional network system, widely distributed in the organs, meridians, and surface of the body.
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Collaterals exhibit characteristics of dispersal along the meridians, extensive distribution, and relative internal-external relationships, enabling the distribution of Qi and blood to all parts of the body.
3. Diagnostic Methods for CollateralsThe diagnosis of collaterals is an important component of TCM diagnostics, involving observation and palpation to assess the morphology, color, and fullness of the collaterals on the body surface.
3.1 Diagnostic Methods
- Observation: Observing the morphology and color changes of the collaterals on the body surface.
- Thenar Collaterals: Located in the superficial veins of the thenar eminence of both hands, reflecting the stomach Qi and spleen-stomach function. Cyanosis is common in cold and pain syndromes; bright red is often seen in heat syndromes; short and pale is common in Qi deficiency syndromes.
- Sub-lingual Collaterals: Referring to the sublingual veins and their branches, reflecting the Qi and blood circulation of the heart, lungs, spleen, and kidneys. Thick and dark purple is common in blood stasis syndromes; thin and light red is often seen in Qi and blood deficiency syndromes; tortuous and cyanotic is common in cold congealing and blood stasis syndromes.
- Facial Collaterals: Located in the superficial veins of the face, especially around the eyes, nose, and temples, reflecting the Qi and blood circulation of multiple organs. Cyanotic veins at the root of the nose are common in pediatric convulsions and abdominal pain; cyanotic veins at the temples are often seen in headaches and migraines; dark-colored collaterals around the eyes are common in liver and kidney Yin deficiency and blood stasis syndromes.
- Interaural Collaterals: Located in the superficial veins behind the ear, reflecting the Qi and blood circulation of multiple organs. Red color is common in heat syndromes; cyanotic color is often seen in cold syndromes; tortuous veins are common in blood stasis syndromes.
- Palpation: Touching the body surface to assess the fullness and elasticity of the collaterals.
- Wrist Collaterals: Located in the superficial veins around the radial artery (at the wrist crease), reflecting the overall Qi and blood circulation. Fullness and good elasticity are often seen in abundant Qi and blood; collapse and poor elasticity are common in Qi and blood deficiency.
- Ankle Collaterals: Located in the superficial veins five cun above the inner ankle, reflecting the Qi and blood circulation of the lower limbs. Fullness and good elasticity are often seen in abundant Qi and blood; collapse and poor elasticity are common in Qi and blood deficiency.
3.2 Key Diagnostic Points
- Shape: Thick and tortuous is common in blood stasis syndromes; thin and short is often seen in Qi and blood deficiency syndromes.
- Color: Cyanotic color is common in cold and pain syndromes; red color is often seen in heat syndromes; dark purple is common in blood stasis syndromes.
- Fullness: Fullness and good elasticity are often seen in abundant Qi and blood; collapse and poor elasticity are common in Qi and blood deficiency.
- Dynamic Changes: Obvious pulsation is common in abundant Qi and blood; weak pulsation is often seen in Qi and blood deficiency.
3.3 Diagnostic Significance
- Judging Pathological Nature: For example, cyanotic color and twisted shape are often indicative of cold and pain syndromes; red color and fullness are often indicative of heat and excess syndromes.
- Determining Lesion Location: Based on the theory of skin areas, the thenar collaterals reflect spleen-stomach function; the sublingual collaterals reflect heart-lung function.
- Predicting Disease Prognosis: Fullness and good elasticity indicate a better prognosis; collapse and poor elasticity suggest a worse prognosis.
3.4 Precautions
- Diagnosis Timing: Conducted at dawn (early morning), when the body’s Qi and blood, Yin and Yang are stable, allowing the collaterals to best reflect their true state.
- Normal and Pathological Colors: It is important to distinguish between them, as the color of collaterals changes with the seasons; cold weather often results in cyanotic or black colors, while hot weather often results in yellow or red colors.
- Comprehensive Judgment: Combine with other diagnostic methods such as observation, listening, questioning, and palpation to improve diagnostic accuracy.
3.5 Clinical Applications
- Cardiovascular Diseases: Thick and dark purple sublingual collaterals are often seen in coronary heart disease and angina.
- Neurological Diseases: Red and tortuous interaural collaterals are often seen in headaches and migraines.
- Digestive System Diseases: Cyanotic thenar collaterals are often seen in stomach cold and stomach pain.
4. Treatment Methods for CollateralsThe treatment of collaterals mainly includes acupuncture and herbal medicine, aimed at regulating the Qi and blood flow in the collaterals, unblocking the collaterals, and improving organ function to achieve therapeutic goals.
4.1 Acupuncture Treatment
(1) Acupuncture Therapy
- Collateral Bloodletting: Using a three-edged needle or filiform needle to puncture the pathological collaterals on the body surface, releasing a small amount of blood to unblock the collaterals and eliminate blood stasis. This is suitable for symptoms such as pain, swelling, and numbness caused by blood stasis and heat toxin accumulation, such as bloodletting at the Weizhong (委中) point for acute lumbar sprain. Strict disinfection should be followed during the procedure to avoid infection, and the amount of blood released should not be excessive to prevent collapse.
- Acupuncture Regulation: Select appropriate acupoints (such as Luo points Lieque (列缺), Zhaohai (照海), and Xi points Qimen (郄门), Jinmen (金门)) based on the condition to regulate the Qi and blood flow in the collaterals. This is suitable for various diseases caused by collateral dysfunction, such as headaches, dizziness, and insomnia. The intensity of stimulation should be chosen according to the patient’s constitution and condition to avoid excessive stimulation.
(2) Moxibustion
- Moxibustion with Moxa Sticks: Ignite moxa sticks and apply them to the acupoints where the collaterals are located for warming stimulation to promote the flow of meridians and harmonize Qi and blood. This is suitable for diseases caused by cold congealing and blood stasis, such as cold abdominal pain and deficiency-cold lumbar pain. Care should be taken with the temperature to avoid burns, and moxibustion should be used cautiously for heat-related diseases.
- Ginger Moxibustion: Place slices of ginger on the acupoints, then place moxa cones on the ginger slices for moxibustion to enhance the warming effect. This is suitable for diseases caused by cold damp obstruction and spleen-stomach deficiency, such as epigastric pain and diarrhea. Care should be taken with the thickness and temperature of the ginger slices to avoid burns.
4.2 Herbal Treatment
(1) Syndrome Differentiation and Treatment
- Treat According to Symptoms: Select corresponding herbal formulas based on the patient’s specific symptoms and pathogenesis. For example, for pain caused by Qi stagnation and blood stasis, Chai Hu Shu Gan San (柴胡疏肝散) can be used; for numbness caused by phlegm-damp obstruction, Er Chen Tang (二陈汤) can be used. This is suitable for various diseases caused by collateral dysfunction, such as headaches, dizziness, and insomnia. Syndrome differentiation should comprehensively consider the patient’s symptoms and signs to avoid one-sided treatment.
- Treat According to Location: Select corresponding herbal formulas based on the location of the lesions. For example, for flank pain caused by liver collateral obstruction, Dan Zhi Xiao Yao San (丹栀逍遥散) can be used; for epigastric pain caused by stomach collateral obstruction, Shi Xiao San (失笑散) can be used. This is suitable for various diseases caused by collateral dysfunction, such as headaches, dizziness, and insomnia. Treatment according to location should combine the overall concept to avoid local treatment affecting the whole.
(2) Treatment from the Perspective of Collaterals
- Invigorate Blood and Eliminate Stasis: Use herbs that invigorate blood and eliminate stasis, such as Dan Shen (丹参), Chuan Xiong (川芎), and Hong Hua (红花), to unblock the collaterals and eliminate blood stasis. This is suitable for symptoms such as pain, swelling, and numbness caused by blood stasis, such as using blood-invigorating formulas for treating coronary heart disease and angina. Care should be taken with patients’ bleeding tendencies to avoid causing bleeding.
- Unblock Collaterals and Alleviate Pain: Use herbs that unblock collaterals and alleviate pain, such as Quan Xie (全蝎), Wu Gong (蜈蚣), and Di Long (地龙), to unblock the collaterals and relieve pain. This is suitable for various pain symptoms, such as headaches, lumbar pain, and joint pain. Care should be taken with the toxicity and side effects of the herbs to avoid excessive use.
- Insect-based Remedies: Use herbs with insect-based properties, such as Shui Zhi (水蛭), Di Long (地龙), and Quan Xie (全蝎), to eliminate stasis and phlegm in the collaterals. This is suitable for diseases caused by long-term illness affecting the collaterals, such as liver fibrosis and rheumatoid arthritis. Care should be taken with the toxicity and side effects of the herbs to avoid allergic reactions.
4.3 Comprehensive Treatment
In clinical practice, acupuncture and herbal treatment are often used in combination to enhance efficacy. For example, for patients with coronary heart disease and angina, blood-invigorating herbal formulas can be administered alongside acupuncture at the collaterals of the pericardium meridian (such as Neiguan (内关)) and Xi points (such as Qimen (郄门)).
4.4 Treatment Principles
· Tonify Deficiency and Drain Excess: Choose appropriate treatment methods based on the deficiency or excess state of the collaterals. Tonify if deficient, drain if excessive.· Adapt to Seasonal Changes: Adjust treatment plans according to seasonal and climatic changes. For example, in spring and summer, it is advisable to unblock the collaterals, while in autumn and winter, it is better to warm and tonify the collaterals.· Combine Syndrome Differentiation and Treatment with Collateral Treatment: On the basis of syndrome differentiation, combine the ideas of collateral treatment to comprehensively regulate the Qi and blood flow in the collaterals.
4.5 Precautions
· Individualized Treatment: Develop personalized treatment plans based on the patient’s specific situation to avoid a one-size-fits-all approach.· Comprehensive Regulation: While treating diseases, attention should be paid to comprehensive regulation, such as diet, emotions, and daily living.· Long-term Treatment: For chronic diseases, long-term treatment should be maintained to avoid discontinuation.References:[1]. Li Jie. Research and Compilation of Collateral Literature [D]. Chengdu University of Traditional Chinese Medicine. 2006.