Feng Ye and Eric Brand
Evaluation of the pulse has been one of the most important aspects of Chinese medical diagnosis throughout history. From ancient times until the modern day, the pulse has been regarded as Chinese Medicine’s most comprehensive and reliable diagnostic indicator. Experienced practitioners can detect ovulation, pregnancy, and common colds in their regular patients; some can even pinpoint a new patient’s chief complaint by the pulse alone. Although many Westerners find the intricate assessment of the pulse to be one of the most intriguing features of Chinese medicine, we are largely unaware of the historical influences that have shaped our modern understanding of pulse diagnosis.
Pulse diagnosis as we know it today is very different than it was at its inception. In the modern age, practitioners rely exclusively upon the radial artery when evaluating the pulse. However, the use of the radial pulse to diagnose visceral conditions was preceded by several other methods of pulse diagnosis. Previous historical periods assessed different conditions and utilized different sites of palpation than we find in the modern day. A variety of factors caused the sites of palpation to change over the ages, and the perception of what the pulse can reveal has evolved to accommodate developments in general medical theory. A brief exploration of this fascinating process is outlined below.
The earliest known references to pulse diagnosis were found in a nobleman’s burial chamber known as Ma Wang Dui, dating back to the early Han Dynasty (168 BCE). At this time, symptoms and diseases were correlated with specific channels and pulses. Although the emphasis is clearly centered on pathoconditions of the channels, a case can be made that the silk records found at Ma Wang Dui illustrate the earliest recorded integration of pulse, pathoconditions, and diagnosis. At this point in history, pulse diagnosis was not yet influenced by five-phase theory or visceral theory.
When the works at Ma Wang Dui were written, there were eleven channels and disease was primarily based upon channel associations rather than visceral origins. Each channel had its own pulse, which was located at a given point on the channel; there were not yet any single points that reflected the pathology of more than one channel. Unusual stirring at the palpation sites indicated disease of the corresponding channel. The various channels were not yet perceived to be linked together, and the channels were labeled with names such as the ear channel and the cheek channel, rather than the modern classification that we find today.
Pulse diagnosis had evolved considerably by the time the Huang Di Nei Jing (“The Yellow Emperor’s Inner Canon”) was written in the later Han Dynasty. At this point in history, Chinese medicine had a clear influence of five-phase theory and visceral manifestation, as well as the twelve channel system that is in use today. The channels were linked with each other, and the concept of “stomach qi is the sea of the twelve channels” arose to explain how the various channels were connected and carried to the radial pulse. The theory of “stomach qi” explained how the wrist pulse could supply information about a variety of organs and channels, and the presence of stomach qi in the pulse is regarded as an important feature of pulse diagnosis to this day.
Another important aspect of pulse diagnosis during the time of the Huang Di Nei Jing involved the comparison of the radial pulse with the pulse of the carotid artery, which was taken at the acupoint ren ying (Man’s Prognosis, ST-9). Determining the strength of the carotid pulse relative to the radial pulse allowed a practitioner to determine which channel a disease was located in. Interestingly, although the radial pulse was assigned a variety of pulse qualities, at this time it was palpated with a single finger. The quality of the pulse determined the location of disease, with each quality specifically assigned to a given channel. This stands in contrast to the modern diagnostic method, which uses the pulse quality to determine the nature of a disease and different locations on the wrist pulse to determine its location.
We find still more clues about the evolution of pulse diagnosis in the Shang Han Lun (“On Cold Damage”), which was written in the Han Dynasty after the Nei Jing. Zhang Ji, the author, mentions that by his time, few physicians were taking the pulse at the older locations of ren ying (ST-9) and the pedal pulse. It is suspected that increasingly conservative attitudes about appropriate touch limited doctors from palpating women’s pulses at the femoral artery and other regions, thus causing physicians to focus their efforts exclusively on the radial pulse. During some dynastic periods, women were kept behind dressing screens and the doctor was only able to palpate the pulse by having her place her cloth-covered wrist through a slot in the screen. Although such influences caused the ancient pulse techniques to go largely undeveloped, they undoubtedly fueled the advancement of diagnosis using the radial artery alone.
Zhang Ji did not differentiate the pulses between the left and right sides. Assigning certain bowels and viscera specifically to the right and left sides appears to be a later development, and the proposed location of some of the bowels and viscera changed over time. Similarly, the concept of using three fingers to take the pulse was a later development, one that is only conclusively evident in the Tang Dynasty works by Sun Si-Miao. Sun Si-Miao’s Qian Jin Yao Fang (“A Thousand Gold Pieces Prescriptions”) text, written in the 7th century, also provide us with the earliest indisputable evidence that the bowels were assigned to the more superficial level of the pulse, while the viscera were assigned to the deeper positions.
However, Sun Si-Miao’s works were preceded by the influential Mai Jing (“The Pulse Canon,” 3rd century CE), written in the Jin Dynasty by Wang Shu-He. This text provides many of the classical descriptions of pulse qualities that are studied to this day. While many different pulse qualities had been named before (over 50 are mentioned in the Nei Jing), many of the pulses named were similar and many were poorly defined.
Wang Shu-He’s Mai Jing provided descriptions of 24 out of the 28 pulses that are used today. By the time of Li Shi-Zhen in the 16th century, we can see 27 of out the 28 pulse qualities that are used in modern times. The final quality, the racing pulse (ji mai), became integrated only in the Qing Dynasty (1616-1911 CE).
It is speculated that numerology may have influenced the number of pulse qualities assigned. 28 is a “divine number” in Chinese numerology; the Chinese recognized 28 constellations in the sky and may have linked the number of pulse qualities with the divine number 28 to reflect their perceived links between the celestial world and the mundane world. The influence of “divine numbers” is most clearly evident in early methods of pulse diagnosis, which made three different groupings of pulses based on the location of the arteries and the associated correspondences with heaven, earth, and man.
The gradual evolution of pulse diagnosis offers us insight into the way ancient Chinese physicians perceived health and illness. Some concepts have remained relatively consistent despite the passage of time, yet the changes that are evident in early texts show us that pulse diagnosis adapted dynamically as Chinese medicine developed. Unfortunately, the ancient methods of palpating a variety of sites never had the opportunity to flourish and provide us with a complete system for use in the modern day. However, whatever factors caused these techniques to diminish in prominence allowed for the development of an extremely sophisticated method of diagnosis based upon the wrist pulse. Although ancient techniques may not always provide us with increased clinical utility, they provide us with insight into the process that allowed Chinese medicine to be the complex and intriguing art that it is today.
“The Dynamic Evolution of Chinese Pulse Diagnosis” is reproduced here with the permission of Eric Brand.