Historical pulse records and practice

One of the earliest references to pulse palpation in CM as a systemised diagnosis technique emerges from the The Yellow Emperor’s Classic of Medicine or Nei Jing, one of the oldest and additionally described as one of the most important Chinese medical texts, compiled in 300–100 bce. The Nei Jing is arranged as two distinct books, the Suwen and the Lingshu, the former being the primary source of information on pulse diagnosis. The Nei Jing is seen as an eclectic book of writings, representing the collation of knowledge representative of a range of different lineage medical teachings extant at its time of writing, and in particular that of systematic correspondences (Hsu 2005) (Box 3.1).

In the context of the radial artery and pulse assessment, the sites of the radial artery were briefly discussed in Chapter 17 of the Nei Jing, described as three positions located above the radial artery, used to ‘detect [the] subtle quality of pulse patterns’ (Lingshu, treatise 74: Ni (trans) 1995: p. 68). These positions, situated at the wrist, adjacent to the radial styloid process and proximal to it, were named Cun, Guan and Chi respectively and were divided into deep and superficial levels of depth. These positions were viewed as representing different regions of the body and some of the positions were linked to specific organs. This meant that a change in the pulse character at the site meant a corresponding change occurring in the related organ.

For using the pulse diagnostically, the Nei Jing introduced two important concepts; that of circulation and the normal pulse . The first of these concepts, circulation, was described as the movement of substances (a vapour called Qi, in various forms, and Blood) throughout the body in 12 linking vessels, located in different regions of the body (Unschuld 1986). The concept of the ‘normal’ pulse was also introduced and this was used as a standard with which to compare the features of an abnormal pulse.

For example in reference to pulse rate the normal pulse was described as:

Therefore distinguishing health by the pulse required comparison of the patient’s pulse with the normal pulse frequency, deviation in the patient’s rate from the normal rate representing illness.

Even this oldest of CM texts borrowed from yet older writings incorporating two distinctly recognisable manuscripts termed the ‘vessel texts’ from the Mawangdui scrolls (Harper 1998, Hsu 2005). These texts include a series of case studies compiled by Chunyu Yi, a Chinese physician, in which Hsu notes in her study of the scrolls that there is ‘sufficient detail to recognize in them a particular form of pulse diagnostics, a form that in many aspects was later discontinued’ (2005: p. 11). In particular, Hsu mentions Chapter 10 of the Lingshu as recording the vessel texts ‘in a strongly modified form, yet in places also verbatim’.

Further evidence of the Nei Jing as a compilation of writings, rather than as a discrete text, is seen in the reference to the use of pulse diagnosis in various forms, including:

In this sense, pulse assessment in the Nei Jing was undertaken from a range of anatomical regions and not exclusively from the wrist.

The Nan Jing, translated as The Classic of Difficult Issues, was produced in response to the ‘difficult issues’ raised, or left unanswered, in the Nei Jing, so constituting an important text in the development of CM diagnostic theory (Box 3.2).

Collated some time in the 1st or 2nd century ce, the first 22 chapters provide instructions on the practical application of pulse assessment, describing a number of palpatory techniques and methods of assessment. The Nan Jing author(s) introduced innovative conceptual ideas for applying the pulse techniques, noting two extraordinary divergences from preceding pulse knowledge. The first was that the circuitous route or cyclic ebb and flow of the ‘Qi and Blood influences’ in the individual channels/vessels logically inferred that these were in fact a single linked circulatory system rather than several discrete circulatory systems as noted in the Nei Jing . Further, if the Qi and Blood flow were linked, then it was only necessary to examine movement at one area along the flow (Unschuld 1985). The ‘inch-opening’ or Cun Kou pulse in the radial artery at the wrist was chosen as the site for assessment because it was thought to be the point at which all the vessels intersected. These ideas were profound to the thinking of Chinese medical practitioners as the time, as noted by Unschuld:

With the publication of the Nan Jing in the 2nd century ce, the regional assessment of the pulse/channel, described extensively in the Nei Jing, was radically challenged with the novel concept of a single or linked circulatory system embodied in the wrist pulse site posited in the book’s ‘first difficult issue’. In doing this, the Nan Jing discussed various methods of examining the pulse at the radial artery. One method of assessment involved each wrist division, Cun, Guan and Chi, divided into two levels of depth, superficial and deep, for the left and right arm radial arterial pulses. This gave 12 pulse positions in total. An acupuncture channel was associated with each of these positions: Yin and Yang organs of each phase respectively associated with the deep and superficial levels of the pulse. Collectively, the 12 pulse positions and ‘pulses’ were termed the Cun Kou or ‘inch opening’. The name and channel arrangement at the pulse positions, and the two depths developed at this time, remain in use (Table 3.1).

Another method of pulse depth examination described in the Nan Jing involved assessing three levels of depth at a single position on the wrist, while another system identified five different levels. The pulse positions were also attributed to different regions of the torso. For example, the Cun positions of the left and right wrist respectively related to the heart and lung. As each of these organs occurred in the thoracic cavity, the upper Jiao, then the Cun positions could be used alternatively to infer the function of the upper Jiao. In this way, one pulse assumption system was overlaid on another.

The Mai Jing, translated as the Pulse Classic (Wang, Yang (trans) 1997), is the oldest extant Chinese medical text devoted solely to the study of the pulse, written in the Jin dynasty sometime in the 2nd to 3rd century ce by Wang Shu-he (Box 3.3). The book symbolizes the apparent flourishing of pulse diagnosis in CM occurring at this time, detailing comprehensive coverage of many aspects of the assessment of the radial pulse, including:

An interesting development in pulse terminology occurred in the Mai Jing . Wiseman and Ye (1999) note that Wang applied a specific pulse ‘name’ to a collective group of descriptive terms, recognising that it is different characteristic features of the pulse such as depth, rhythm, rate, width and length that combine to produce a particular pulse quality. For example, rather than ‘sinking and frail, and one can palpate it only deeply’ (Ni 1995: p. 74) found in the Nei Jing, the Mai Jing attributed this group of descriptive terms to the Weak pulse (ruò mài). With the introduction of specific pulse names, this meant that the identification of a specific pulse quality now hinged on the recognition of all aspects of the pulse (Wiseman & Ye 1998).

The Mai Jing details 24 specific pulse qualities and the description of pulse qualities associated with specific disease states. Variations of strength, rhythm, speed and contour of the presenting pulse are discussed in terms of organ function and in terms of the channel system.

The Mai Jing is particularly well regarded for its lengthy commentary on the interpretation of these pulse qualities relating to pathology. There is an extensive discussion of the clinical significance of abnormal pulse qualities occurring in each of the specific pulse positions of Cun, Guan and Chi and the symptoms accompanying them. For example, Vacuity and Repletion patterns affecting the Lungs were diagnosed by the simultaneous increase or decrease in strength at the Lung position of the pulse (this being the deep level of depth at the Cun position on the right wrist). Additionally, the 24 pulse qualities had different diagnostic meaning when occurring at the individual pulse positions. For example, a Floating pulse at the right Cun position meant fever and headaches, the Tight pulse meant cold damage and the Rapid pulse meant vomiting (Table 3.2). At the Guan position, the Floating pulse meant there was abdominal fullness and no appetite, the Tight pulse meant fullness below the heart with acute pain and the Rapid pulse meant guest heat in the stomach. Floating pulse in the Chi position meant wind heat in the lower Jiao with difficult urination, Taut pulse meant pain due to cold and the Rapid pulse here meant aversion to cold and wind and pain below the umbilicus. In this way, Wang Shu-He constructed a comprehensive and detailed approach to the clinical interpretation of pulse. From the time of the Mai Jing throughout the centuries till today, authors continue to reiterate the definitions of the pulse as stated in this book.

The Bin Hue Mai Xue was written by Li Shi Zhen in 1564 ce. The book used the Cun Kou or three radial arterial sites method of pulse diagnosis in combination with the overall pulse qualities introduced in the Mai Jing with positional and pulse depth dimensions. Consequently the book is a collation of older literature on the pulse and so descriptions from the Nei Jing are found alongside information from the Mai Jing and other texts such as the Pulse Knacks (Li, Flaws (trans) 1998). The author also introduced several more pulse qualities into the general CM nomenclature and provided commentary on comparative differences of each pulse type (Box 3.4).

The book was meant for memorisation, so it was written in a series of rhymes, detailing the pulse description and related indications. These rhymes would also have doubled as a mnemonic in clinical practice; the practitioner would feel the pulse and recite the rhymes, so identifying the pulse type being felt.

The book is significant in the history of pulse diagnosis in that it was collated as a summation of all pulse knowledge extant at the time of its writing. Li Shi Zhen organised this knowledge into a comprehensible and accessible format. The book has been an important educational tool and a guide for CM students learning pulse in China since the 16th century and is still used today.

Although the supremacy of wrist diagnosis is argued clearly in the historical record of CM with the Nan Jing, the theoretical and logical argument presented was counter to the notion that the circulatory system serves more than just the organs. The circulatory system distributes blood and fluid to the muscles, skin, tissue and into the periphery in addition to the organs; both localized and systemic requirements are placed on the circulation. In this sense it is logical that pulses in other regions of the body should also play a vital role in the assessment of an individual’s health, and historically, this is what happened.

In the early centuries of the first millennium ce, pulse assessment encompassed examination of the pulse at numerous regions throughout the body. This was the basis of what is termed regional pulse assessment : the assessment of arterial pulse sites that occurred in regions of the body other than the Cun Kou. In the Nei Jing and other CM literature classics, there is reference to at least three distinct groupings of regional pulses. There are the three permanent pulses, of which the Cun Kou is one; the pulse sites linked with the actual anatomical location of each of the channels; and the Nine Continent pulses. Of the three groupings it is the only the Nine Continent system that is still regularly covered in contemporary CM literature, as the system provides clinically relevant information not gained from the Cun Kou system (Box 3.5).

Interestingly, Kuriyama (1999) notes that in spite of the Nan Jing, the use of other regional/anatomical pulses other than that of the wrist was never totally discarded by ancient Chinese practitioners. Vestiges of the regional assessment system of pulse were retained in the Shan Han Lun, Mai Jing and Jin Gui Yao Lue (Kuriyama 1999: p. 45). For example, the Jia Ji Jing (Systematic classic of acupuncture and moxibustion), which was written approximately two centuries after the Nan Jing, incorporated segments of the Nei Jing (Lingshu, Chapter 9) speaking specifically of using the assessment of different pulses around the body from the regional pulse sites to assess health through the similarity of pulse strength occurring at all these sites. The Jia Yi Jing clearly states that the Mai Kou and Ren Ying pulses are used to determine the presence of ‘surplus’ or ‘insufficiency’ of Yin and Yang and determine balance or imbalance (p. 301: in a postscript note from the translators, the chapter was derived from Chapter 9 of the Lingshu):

Additionally, the Mai Jing, another text postdating the Nan Jing’s discussion on the use of a single arterial site for pulse assessment, also incorporated regional pulse assessment. Chapter 28 of the Mai Jing states:

(The translator’s note to this chapter points out that ordinarily the wrist and carotid pulses should vary in strength, size. For these to be congruent represents serious disturbances to the Qi and blood flow.)

There are two explanations as to why the authors of the Mai Jing and Jia Ji Jing included regional pulse site assessment. The first is they did this through reverence of the older text. The second is that the regional pulse sites did in fact provide clinically useful information, probably information that could not be obtained or provided by the assessment of the Cun Kou pulse alone.

It is also apparent that the regional channel/pulse assessment system lingered into later centuries with commentators of the Nan Jing, Lu Kuang (3rd century ce) and Yang Hsuan-ts’ao (7th/8th century ce), linking the channels with regional pulses located in anatomical regions other than the wrist. That is, the knowledge was still extant. For example, in their commentaries on the first difficult issue, they state:

Lu and Yang respectively refer to the popliteal, temple(?), dorsalis pedis (ch’ung), carotid (jen-Ying) arteries in addition to the radial artery (ta-Ying). All sites were distinct from other anatomical regions as having a movement present. In this sense, there were several circulatory pathways.

Yet, as Unschuld noted, the argument presented by the Nan Jing was convincing, for by the 11th century the Nan Jing commentaries distinctly changed, with only minor references to the regional pulses in the text mainly in ‘gentle’ condemnation of antecedent medical scholars’ comments (Yu Shu, in Unschuld 1986: p. 96). It appears these later medical scholars accorded little value to the region pulse system, beyond interest as a curious historical artefact. Additionally, rather than the assessment of arterial segments these authors linked these pulse sites with discrete points or sites. These were increasingly being cited as acupuncture points rather than the channel artery coupling located in the holes or grooves provided by the anatomy. For example, the tibial arterial pulse was discretely located at KD 3 (Taixi). Interestingly, the commentaries of the Nan Jing as compiled by Unschuld chart the fracturing relationship between the arterial pulses and the channels with the course of the channel being separated from that of an associated arterial segment.

What is certainly apparent in the commentaries of the Nan Jing and reflected in the classics generally, is the temporal change in authors’ attitudes to the regional pulse system: from a necessary skill in the time of the Nei Jing to a historical relic by the end of the first millennium and finally forgotten by the time of the European Renaissance in the 16th century. In the Bin Hue Mai Xue, published in 1564, there is no reference to the regional pulse system in spite of the book being a summation of historical pulse literature.

In some ways, the loss of regional pulse assessment according to Hsu (2005) probably reflects the integration of philosophical doctrines of Confucian ideology into Chinese society in the first millennium, where modesty constraints meant body palpation, whether pulse or anatomically related, was condoned only within the confines of discrete, and socially acceptable, anatomical regions (Hsu 2005). In contemporary times, the societal context of the practise of CM means minor surgical procedures once associated with the practice of acupuncture, in which regional pulse assessment probably served an important purpose, are no longer carried out.

Besides being a historical record of the development of pulse diagnosis, the classics highlight the conceptual variation and conflict apparent in the practice of pulse diagnosis through the centuries and up to the present day. This can be seen in the change in pulse position and organ correlation. For example, the Bin Hue Mai Xue mentioned only five Yin organs. The superficial Yang organs were seen simply as an extension of these, and are not mentioned. In contrast, the Mai Jing listed all 12 organs as distinct and separate entities with each given a distinct pulse depth and position. Theoretical preconceptions shaped the development of pulse taking and were in turn shaped by practice. In the Bin Hue Mai Xue the Pericardium, Bladder and Triple Heater organs were theoretically connected to the Kidneys via internal channel pathways and subsequently were seen as an extension of the Kidneys. For the purposes of pulse taking, this meant the division of the Chi positions into two subcategories; Kidney Yang and Kidney Yin. The Pericardium, Bladder and Triple Heater were not specifically mentioned.

There are also major differences in the division of the variable depth between texts. For example, the Nei Jing mentioned only two pulse depths, superficial and deep, while the Mai Jing and Bin Hue Mai Xue listed three, with the addition of a middle level of depth. The Nan Jing listed anywhere from three to five levels of depth; individual organs, organ systems and body substances such as Blood were simultaneously assigned to each position. Alternatively, the Cun, Guan and Chi pulse positions may be seen to reflect the upper, middle and lower (Heaters) portions of the torso (Maciocia 2004, Ho & Lisowski 1997) or may reflect individual organs (Flaws 1997). The positions can be used to assess overall pulse qualities or used individually for specific organ characteristics.

According to Birch (1998) the apparent conflicts in the classics stem from the historical (and contemporary) diversity of CM practice and the conceptual systems they reflect. This reflects the syncretistic tendency, throughout the history of CM thought, for many different theories, often conflicting, to exist side by side (Unschuld 1985). Accordingly, this meant the reconciliation of opposing ideas rather than a resolution of the contradictory views. This is apparent in assumption systems used to interpret radial pulse information and in the specific pulse terminology itself. Unschuld, in his commentaries on the Nan Jing, perhaps best describes the coexistence of theoretical variation:

Unschuld’s view has been borne out by the attempts of some commentators on the CM literature to reconcile the ‘occasional’ conflicting information contained in different texts through tenuous theoretical linkages rather than direct questioning of theoretical foundations. Others have refuted it altogether, maintaining their conservative views in relation to the original source texts. However, the old is often retained with the new, to the point of conflict. This is demonstrated by Unschuld’s translation of the commentaries of Hsu Ta-ch’un, an influential physician scholar and medical writer of the 18th century ce. Unschuld notes that while Hsu’s commentaries focused extensively on the Nan Jing, he did not acknowledge the book’s ideas and contribution to the development of pulse diagnosis. Instead he criticised the Nan Jing in favour of the ideas originally presented 200 years earlier in the Nei Jing, not because they were more clinically relevant (in fact they were very ambiguous), but rather because they were simply ‘older’ (Unschuld 1990). This resolution of theoretical differences has never been a strong point of CM theoreticians.

In contemporary CM practice, not much has changed. Today, a number of different systems are still used to interpret variations in the pulse, and they invariably incorporate a number of untested assumptions from the classics concerning the normal presentation of the pulse. Some of these systems are related, and so the interpretation and understanding of the theory can be reconciled. Other pulse assumption systems appear quite contradictory, and reconciling the opposing interpretation is difficult if not impossible. Further complication arises from the development of new and novel pulse systems in recent years. Old problems thus continue to appear in the modern context.

Nowadays there are additional problems to contend with. The first is the assumption that knowledge documented in the classical literature is based on empirical evidence gathered from a broad range of experiences. However, there is no clear evidence of this and so some of the knowledge could be derived from a single case study based on an individual’s observation, as is the nature of empirical observation. This makes extrapolation of the knowledge within these books to a broader population base a fraught process. Secondly, pulse diagnosis also largely continues to be reliant on information first presented nearly 2000 years ago and so it is also necessary to contextualise the temporal authorship of the content material in the classics. For example, there are whole chapters in the classical literature devoted to prognosis of impending death. Such knowledge needs to be tempered with the realization that developments in emergency medicine mean that the physiologic impairment to organ structures causing these pulses to form may now be addressed with surgical intervention, dialysis or other forms of therapy now available. Hammer (2002) best summarises this:

In contemporary practice, academics and practitioners continue to consult the classics. It is rare to find any writings about the pulse without some ‘validation’ through direct or overt inferences and connections to these books. However, it can be conjectured that the classics have possibly hindered the development of CM pulse diagnosis as much as they have preserved it. This is best illustrated by comparing two treatises on the use of pulse in medicine published at similar times, both important for pulse diagnosis but for different reasons. The first is Li’s Bin Hue Mai Xue . The second is Harvey’s Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus [Anatomical Essay on the Movement of the Heart and Blood in Animals] (1624). The texts were published in the late 16th and early 17th century ce respectively and were deemed important works by the authors at those times. Harvey proved the circulation of blood and described the pulsations as the impulse or pressure flow of blood, an event of cardiac contraction (Naqvi & Blaufox 1998). Li focused on collating and annotating earlier CM texts relating to pulse diagnosis, providing a summary of extant works of his time and expanding on some specific pulse qualities. However, although both these works concentrate on the pulse they are starkly contrasted in one very important way. Where Harvey endeavoured to inform practice of pulse diagnosis through ongoing exploration of the underlying principles of pulse, Li Shi-Zhen revisited the books of earlier scholars and reinforced classical methods of pulse diagnosis. Li Shi-Zhen’s writing was in effect the embodiment of a culture that revered and respected its past, while Harvey’s embodied the deducted logic of practice based on cause and effect that was to become the defining element of biomedical practice.

Interestingly, although there were conceptual links between the heart and vessels described in the CM classics such as the Nei Jing, the pulse continued to be viewed in terms of the flow of Qi influences; ‘there is no indication as to a conceptualisation of either the heart or the lung as fulfilling any kind of a pump like or bellow like function in the classics’ (Unschuld 1985: p. 76).

Overall, and in spite of the conflicting views, CM has maintained throughout its history and into contemporary practice a focus on the significance of each individual radial pulse site as being reflective of a specific part of the body. The Cun, Guan and Chi pulse sites are associated with information unique to its location within a given segment of artery. Theoretically, this is associated with palpatory differences in the pulse characteristics between the three pulse positions for each arm. This is in contrast to ancient Greek diagnosticians such as Galen, and even modern biomedical practices that envisage no difference in the pulse and the information obtained when feeling it at different places on the same arterial segment.