▲Click the blue “Nan Ke Yi Meng” above to followDaily progress in TCM brings joyLingxi Note:In TCM tongue diagnosis, the observation of the sublingual collaterals (their thickness, length, color, arrangement, distortion, nodules, etc.) reflects the state of Qi and blood in the body (normal, deficiency, blood stasis).In TCM, examining the tongue and pulse is essential; many people only look at the tongue surface and neglect the sublingual area, unaware that the sublingual collaterals are a quick way to observe Qi and blood. The sublingual collaterals are the two bluish-purple vessels located on either side of the lingual frenulum, also known as the lingual veins. By observing the color and shape of these vessels and their branches, one can roughly determine whether the Qi and blood flow is smooth and assess the coldness or heat of the blood and Qi. The sublingual collaterals have significant diagnostic value in identifying blood stasis syndromes.Method for Examining Sublingual CollateralsSit quietly in a well-lit area, lift the tongue towards the hard palate at about a 45-degree angle, but do not exert too much force; keep the tongue relaxed to avoid creating a false impression.The “sublingual collaterals” will then be visible.Use your eyes or a magnifying glass to observe the color and shape changes of the “sublingual collaterals”.First, examine the large collaterals running vertically on either side of the lingual frenulum, typically one on each side, though there may be two or more. Observe any changes in color and the thickness and length of the vessels, noting if they are distended, curved, or constricted.Next, check the surrounding small collaterals for color changes and any signs of distension or nodules.Simultaneously, reference the size, color, and quality of the tongue muscle for a comprehensive observation.
Criteria for Normal and Abnormal Findings
1. Normal color and shape of the sublingual collaterals.1. The large sublingual collaterals can have three forms: single, double, or multiple branches.Length:Measured along the longitudinal axis of the tongue, if less than 1/2 of the tongue length, it is considered short; if more than 1/2, it is long.Thickness:The diameter of the large collaterals is about 2 mm or less; if greater, it is considered thick, and if less, thin. The base is slightly raised, and the upper end is flat. Normal vessels do not appear excessively thick or long, nor thin or short, and their color is generally dark red with a bluish tint, without signs of cyanosis, pale purple, purplish-red, or light red.2. The small sublingual collaterals (the branches surrounding the large collaterals) are typically pink and form a dense network, with some not visible externally. 2. Abnormal “sublingual collaterals” and their main symptoms.Distinguish the changes in color and shape of the “sublingual collaterals” from the normal ones, and combine this with clinical pulse symptoms for judgment.1. If the “sublingual collaterals” are bluish-purple, with a long, distended shape or short, constricted form, and the small collaterals are bluish-purple or dark red and distended or without nodules, this indicates Qi stagnation and blood stasis or phlegm-dampness (commonly seen in conditions like accumulation, distension, heart pain, phlegm obstructing blood stasis, coughing blood, abdominal distension, gynecological menstrual disorders, and painful menstruation).2. If the “sublingual collaterals” are pale purple or blue, with a long, distended shape or short, constricted form, and the small collaterals are pale purple or dark red and distended or have small nodules, this indicates cold accumulation or Yang deficiency leading to Qi deficiency and blood stagnation (commonly seen in conditions like chest obstruction, heart pain, stroke with hemiplegia, numbness, edema, abdominal cold pain, and gynecological menstrual disorders, painful menstruation, amenorrhea).3. If the “sublingual collaterals” are purplish-red, with a long, distended shape or short, constricted form, and the small collaterals are dark red or light blue and distended or have small nodules, this indicates heat obstructing blood stasis or dampness obstructing blood stasis (commonly seen in conditions like warm diseases with heat entering the blood, surgical abscesses, damp-heat jaundice, edema with dampness and stasis, abdominal distension, and blood stasis headaches, menstrual disorders, painful menstruation, menorrhagia, and arthralgia).4. If the “sublingual collaterals” are light red or light blue, with a small and short shape, and the small collaterals show little change, this indicates Qi deficiency and blood weakness, or a combination of stasis (commonly seen in chronic wasting diseases, Qi deficiency and blood loss, deficiency syndromes, indigestion, chronic diarrhea, abdominal pain, and gynecological cold womb infertility, menstrual disorders, painful menstruation, amenorrhea, menorrhagia, and leukorrhea).The Relationship Between Sublingual Collaterals and the Organs, Meridians, Qi, and BloodThe “sublingual collaterals” are distributed beneath the tongue and have a direct connection to the Qi and blood of the organs through the meridians.“The tongue is the sprout of the heart,” “the hand Shaoyin heart meridian connects to the base of the tongue,” “the foot Jueyin liver meridian connects to the base of the tongue,” “the foot Taiyin spleen meridian connects to the base of the tongue and disperses beneath it,” and “the foot Shaoyin kidney meridian connects to the base of the tongue.”Although the hand Taiyin lung meridian does not connect directly, the lung system communicates with the throat and connects to the base of the tongue, indicating that the Qi and blood of the organs are all connected to the tongue through the meridians. Therefore, any cold or heat, deficiency or excess in the Qi and blood of the organs will inevitably reflect in the upper part of the body, particularly in the “苗窍” (orifices) of tongue diagnosis, and the “sublingual collaterals” are the direct vessels connecting the Qi and blood of the organs to the tongue. Changes in the shape and color of the “sublingual collaterals” are often the first signs of organ Qi and blood disorders, especially evident in blood stasis syndromes. The relationship between the changes in the shape and color of the sublingual collaterals and the pathogenesis is closely related to the cold and heat of the organs and the deficiency and excess of Qi and blood. The changes in shape and color are generally: deficiency leads to pale red, small, and short; stasis leads to bluish-purple, distended, and long; cold leads to pale purple and constricted; heat leads to purplish-red and thick. The relationship is particularly close with the heart, liver, and spleen organs.In summary, the color changes of the “sublingual collaterals” indicate that “stasis leads to dark colors, deficiency leads to light colors.” The changes in shape, with distended and long vessels, often indicate Qi stagnation and blood stasis, while thin and short vessels often result from cold accumulation or Yang deficiency leading to poor blood circulation. The distribution of the large sublingual collaterals, whether single or multiple branches, is a normal physiological phenomenon and not pathological.The Relationship Between Changes in the Shape and Color of the Sublingual Collaterals and Individual Differences, Disease Stages, and Seasonal ChangesThe changes in the shape and color of the “sublingual collaterals” are generally consistent with clinical diagnoses. Individual variations, different stages of disease, and seasonal changes can lead to discrepancies. For example, in the early stages of stroke with hemiplegia, the “sublingual collaterals” often appear pale purple or bluish-purple, distended, and long; after a prolonged illness, they may appear pale red and short. In cases of dysmenorrhea, changes in the “sublingual collaterals” are often observed before the onset, while they may appear atypical after relief. Additionally, conditions like “chest obstruction due to phlegm and blood stasis” often show significant changes in the “sublingual collaterals” during seasonal transitions from winter to spring, while changes are less pronounced in summer and autumn. Furthermore, age and temperature variations can also lead to slight differences.The Relationship Between Changes in the Shape and Color of the Sublingual Collaterals and Changes in Tongue QualityThe changes in the shape and color of the “sublingual collaterals” are generally consistent with changes in tongue quality observed clinically.For instance, if the tongue quality shows purple spots or dark red, the “sublingual collaterals” often appear bluish-purple, pale purple, or purplish-red, with a distended and long shape, indicating a stasis condition.However, there are instances of inconsistency, such as a tongue quality that is pale red and plump indicating deficiency, while the “sublingual collaterals” show bluish-purple, distended, and long, indicating excess. Additionally, some tongue qualities may show purple spots or dark red indicating Qi stagnation and blood stasis, while the “sublingual collaterals” may appear pale red and short, indicating Qi deficiency and blood loss. These phenomena often occur when there is a combination of deficiency and excess, or a mix of cold and heat.Therefore, in clinical differentiation, it is necessary to conduct a detailed analysis considering the etiology, pulse symptoms, and stages of the disease to discern the true from the false and clarify the primary and secondary conditions.
