In the theoretical study and practice of pulse diagnosis, some clinical manifestations of pulse patterns are not clearly described by ancient scholars, leading to many modern TCM practitioners having a vague understanding of certain theoretical issues in pulse diagnosis. For example, the tactile characteristics of the Ru Mai (濡脉, Ru Pulse) were described by ancient texts as feeling like silk floating on water; when lightly pressed, it gives a soft and weak sensation, and when pressed harder, it becomes imperceptible. However, later generations have categorized this pulse phenomenon under the category of Fu Mai (浮脉, Floating Pulse).
The Ru Mai is associated with internal damage from deficiency, dampness obstructing the body, or excessive dampness, and in later discussions of pulse diagnosis, it is often classified under the category of Fu Mai. The question arises: can the Ru Mai coexist with the Chen Mai (沉脉, Chen Pulse)? Most TCM scholars would deny this possibility. If it were possible, it might lead to controversies regarding the theoretical understanding of pulse diagnosis, seemingly contradicting the theory of the Ru Mai, but this is not necessarily the case.
I believe that the theoretical knowledge left by our predecessors should be reanalyzed, re-understood, and re-recognized with a rigorous scientific attitude, especially the more difficult concepts. Therefore, it is necessary to discuss whether the Ru Mai can appear in combination with the Chen Mai.
Li Shizhen stated, “The Ru Mai is extremely soft and fine, like cotton in water; it feels light to the touch, and when pressed, it is imperceptible, like bubbles floating on water (浮沤, floating bubbles).” In his poem in the Bin Hu Pulse Theory, he wrote, “Floating and soft, fine indicates Ru; sinking, fine, and soft (sinking is without strength) indicates weakness; if it is slight, it floats lightly as if about to disappear, and fine comes close to being sinking and slight.” This means that the characteristic of the Ru Mai is floating and fine, and it should be distinguished from weak, slight, and fine pulses that resemble Ru. Subsequently, during the early Qing Dynasty, physician Li Yanhe provided a detailed explanation of the Ru Mai in the Pulse Theory Compendium, stating, “Ru means soft. It must be seen as fine and soft in the floating phase; if in the middle or sinking phase, it cannot be perceived.” This may be the theoretical basis for those who argue that the Ru Mai cannot appear in the Chen Mai, and later scholars have accepted the classification of Ru Mai as belonging to the Fu Mai category.
I believe that the statements in the Bin Hu Pulse Theory and the Pulse Theory Compendium regarding “floating and soft, fine indicates Ru” and “in the middle or sinking phase, it cannot be perceived” do not imply that the Chen Mai cannot exhibit the Ru Mai; rather, it suggests that the Ru Mai can manifest in another form within the Chen Mai. This phenomenon indicates that the Ru Mai has a distinct floating, soft, and weak sensation when taken in the floating phase, while in the middle and sinking phases, it may exhibit the characteristic of being “imperceptible.” When we revisit the description of the weak pulse in the Bin Hu Pulse Theory as “sinking, fine, and soft indicating weakness,” it seems that the elder also had doubts about the combination of “soft, fine, and sinking” pulse patterns. After all, the perception of “weak pulse, extremely soft and sinking” will always carry a sense of “weakness and lack of strength…”
In fact, the clinical manifestation of a sinking, fine, and Ru Mai pulse can be observed. Some conditions of internal dampness may present with a sinking pulse, yet the fine, soft, and weak sensation can still be carefully observed. Therefore, the statement “in the middle or sinking phase, it cannot be perceived” refers to the unique manifestation of the Ru Mai that is difficult to feel in the sinking phase, which is characteristic of the Ru Mai. It is evident that this phenomenon is also a normal pulse pattern as described in the Pulse Theory Compendium. We have not fully understood the intentions of our predecessors, and we have misinterpreted the pulse manifestations of “light touch, imperceptible, like bubbles floating on water” and “in the middle or sinking phase, it cannot be perceived” as meaning that the Ru Mai only appears in the Fu Mai, leading to the notion that the Ru Mai belongs solely to the category of Fu Mai for hundreds of years. Shouldn’t we, as successors of TCM, reconsider this with care?
In my work, Expert Techniques in Folk TCM Pulse Diagnosis: Ru Mai, I continue to describe the characteristics of the Ru Mai as “floating and soft, fine indicates Ru” and “in the middle or sinking phase, it cannot be perceived.” However, the theories of our predecessors do not deny the possibility of the Ru Mai existing within the Chen Mai. For the systematic theory of pulse diagnosis, it still requires the continuous practice and summarization of experiences by later generations to develop and refine it. Therefore, I have cited examples of the combination of Ru Mai and Chen Mai in conditions such as (3) phlegm-damp obstructing the lungs, cough, (11) cold-damp injuring the spleen, (15) spleen and kidney yang deficiency, leading to floating edema, and (16) kidney yang deficiency causing cold-damp lower back pain, to discuss with predecessors and to provide a basis for our medical practice and continuous exploration.
The combination of Ru Mai and Chen Mai is often seen in inflammatory diseases of the viscera and lower jiao. When encountering a sinking, fine, and Ru Mai pulse or a sinking, fine, and slippery pulse, practitioners should be highly vigilant to prevent the misunderstanding that the Chen Mai cannot exhibit the Ru Mai, which may lead to missing treatment opportunities for serious conditions or the onset of major diseases.