Pulse diagnosis

Pulse diagnosis (PD) is a diagnostic tool used for over 3000 years in various Oriental countries, which classifies pulse signals from different health conditions and serves as an important reference for clinical diagnosis and home monitoring.^[1] It is a diagnostic technique used in traditional Chinese medicine, Ayurveda, traditional Mongolian medicine, Siddha medicine, traditional Tibetan medicine, and Unani.

Traditional Chinese medicine

Pulse diagnosis is one of the most representative special diagnostic methods in traditional Chinese medicine (TCM) and has been emphasized by various generations of medical practitioners in the long history of development. It remains widely used in clinical practice in China today and continues to serve as an important method of diagnosis in TCM.^[2]

The main sites for pulse assessment are the radial arteries in the left and right wrists, where it overlays the styloid process of the radius, between the wrist crease and extending proximal, approximately 5 cm in length (or 1.9 cun, where the forearm is 12 cun). In traditional Chinese medicine, the pulse is divided into three positions on each wrist. The first pulse closest to the wrist is the cun (inch, 寸) position, the second guan (gate, 關), and the third pulse position furthest away from the wrist is the chi (foot, 尺).^{[citation needed]}

There are two main systems of diagnostic interpretation of pulse findings utilised in the Chinese medicine system. The first is eight principle diagnosis (Cun Kou) utilise overall pulse qualities, looking at changes in the assessed parameters of the pulse to derive one of the traditional 29 pulse types. The traditional 29 pulse types include Floating, Soggy, Empty, Leathery, Scattered, Hollow, Deep, Firm, Hidden, Long, Surging, Short, Rapid, Hasty, Hurried, Moderate, Slow, Knotted, Full, Thready, Minute, Slippery, Choppy, Wiry, Tight, Weak, Regularly intermittent, rapid-irregular, and Stirred. They are analyzed based on several factors, including depth, speed, length, and fluid level. Some pulses are a combination of more than one factor.^[3]

The second approach focuses on individual pulse positions, looking at changes in the pulse quality and strength within the position focused on the cause and not the symptoms, with each position having an association with a particular body area.^[4] For example, each of the paired pulse positions can represent the upper, middle and lower cavities of the torso, or are associated individually with specific organs. (For example, the small intestine is said to be reflected in the pulse at the left superficial position, and the heart at the deep position.)

Various classic texts cite different arrangements to the pairings of organs, some omitting the second organ from the pulse entirely while others show organ systems reflecting the acupuncture channels (Wuxing, five phase pulse associations), and another the physical organ arrangement used in Chinese herbal medicine diagnosis (Li Shi Zhen^[5]). Generally, the commonly used organ associations are: first position on the left hand represents the heart in the deep position and small intestine is in the superficial position, the second, deep is the liver and superficial is the gallbladder, and third the kidney yin is deep and the bladder superficial. On the right hand, the first deep position is representative of the lungs and superficially the large intestine, the second of the spleen and stomach, and the third represents the kidney yang at a deep level and uterus or the pericardium and the san jiao in the deep position. The strengths and weaknesses of the positions are assessed at 3 depths each, namely fu (floating or superficial, 浮), zhong (middle, 中) and chen (deep, 沉).^[6] These 9 positions are used to assess the patient diagnostically, along with the different qualities and speed of the pulse.^[7][8]

29 Pulse Types

Classical texts and modern interpretations describe 29 distinct pulse types, each with specific characteristics and clinical implications. These include^[9]:

1. 

   Fu Mai 浮脉

   浮脉 Fu Mai (Floating, Superficial): Located in the exterior. With the finger raised, it has a surplus; when pressing down it is insufficient, weak, or disappears. When pressure is released, it regains full strength.
2. 洪脉 Hong Mai (Surging, Flooding): Floating, large (wide), comes on exuberant, departs debilitated. "Coming onto the shore with force and retreating without force."
3. 革脉 Ge Mai (Leathery, Drumskin, Tympanic, Hard): Bowstring and large with an empty center; feels like the head of a drum. Floating, large, hard, and resistant to pressure.
4. 芤脉 Kou Mai (Hollow, Scallion Stalk, Green Onion): Floating, soft, large body but empty in the center. Forceless—large and weak.
5. 濡脉 Ru Mai (Soft, Soggy): Floating, fine, soft, and flexible. Can be felt with light pressure but disappears with heavy pressure. "Like a silk thread in water."

6. 

   San Mai 散脉

   散脉 San Mai (Scattered): Floating, large, without root; with light pressure it is irregular and chaotic; with heavy pressure it is impalpable. "Like wind blowing hair or scattered leaves."
7. 虚脉 Xu Mai (Forceless, Empty, Deficient): A generalized term for forceless pulses; floating, large, slow, empty, soft, and weak.
8. 沉脉 Chen Mai (Deep): Located near the bone. Cannot be detected with light or moderate pressure but felt with heavy pressure.
9. 伏脉 Fu Mai (Hidden): Very deep, difficult to feel, under the sinews, requiring heavy pressure to obtain.
10. 牢脉 Lao Mai (Firm, Confined): Not felt superficially, only with heavy pressure. Hard, firm, large, bowstring, and long.
11. 弱脉 Ruo Mai (Weak): Deep, fine, soft, like a thread.

12. 

    Chi Mai 迟脉

    迟脉 Chi Mai (Slow): Below 60 BPM or less than 4 beats per practitioner's breath.
13. 缓脉 Huan Mai (Slowed down, Moderate, Relaxed): Level and harmonious, relaxed and forceful. About 60 BPM, beats come and go slowly.
14. 涩脉 Se Mai (Choppy, Hesitant): Slow, stagnant, difficult, fine, may stop and lose a beat but then recovers. Feels like a knife scraping bamboo.
15. 结脉 Jie Mai (Knotted, Bound): Slow, relaxed, stops at irregular intervals.

16. 

    Shi Mai 实脉

    实脉 Shi Mai (Excess, Full, Replete, Forceful): Bowstring, large, hard, and replete, with surplus at all three positions.
17. 滑脉 Hua Mai (Slippery, Rolling): Smooth, flowing, uninhibited; feels like pearls rolling in a dish.
18. 紧脉 Jin Mai (Tight, Tense): Tight, strong, feels like a taut or twisted rope.

19. 

    Chang Mai 长脉

    长脉 Chang Mai (Long): Long and felt beyond its normal location, extending past the cun position.
20. 弦脉 Xuan Mai (Wiry, Taut): Straight, long, tense, like pressing a tight string of a musical instrument.
21. 微脉 Wei Mai (Minute, Faint, Indistinct): Extremely fine, soft, barely palpable, sometimes lost.
22. 细脉 Xi Mai (Thready, Thin): Soft, like a silken thread, weak but not scattered by pressure.
23. 短脉 Duan Mai (Short): Does not extend to its full range; most distinct at the Guan position.
24. 代脉 Dai Mai (Regularly Intermittent): Relaxed and weak, stops at regular intervals, sometimes long.

25. 

    Shuo Mai 数脉

    数脉 Shuo Mai (Rapid): Above 90 BPM, or more than 5 beats per breath.
26. 疾脉 Ji Mai (Racing, Swift, Hurried): Very rapid, over 120 BPM, or 7–8 beats per breath.
27. 促脉 Cu Mai (Rapid-Irregular, Skipping, Abrupt): Rapid and irregularly interrupted.
28. 动脉 Dong Mai (Moving, Throbbing, Stirring): Slippery, rapid, forceful, feels like a bean—strong and throbbing abruptly.
29. 大脉 Da Mai (Large, Big): Large, fills up the fingertip, forceful. Similar to the Surging pulse but without the wave-like shape.

Computational pulse diagnosis (CPD)

A typical wave form of pulse

Computational pulse diagnosis (CPD) is a technique that applies modern sensing and computational methods to the traditional practice of pulse diagnosis. Conventional pulse diagnosis (PD), widely used in Chinese and other traditional medical systems, relies on tactile assessment of the radial artery to evaluate pulse shape, rhythm, and strength, but its results vary with practitioner experience and training. CPD seeks to replicate this process by employing sensors to capture wrist pulse signals and algorithms to process and analyze them. The procedure typically involves four stages: signal acquisition, preprocessing, feature extraction, and recognition. Advances in machine learning and signal processing have enabled CPD to be investigated for applications in cardiovascular, metabolic, and other health conditions. While significant progress has been reported in both experimental studies and clinical applications, further work is needed to establish standardized datasets and evaluation benchmarks.^[10]

Traditional Indian medicine (Ayurveda and Siddha-Veda)

Ayurvedic pulse measurement is done by placing index, middle and ring finger on the wrist. The index finger is placed below the wrist bone on the thumb side of the hand (radial styloid). This index finger represents the Vata dosha. The middle finger and ring finger are placed next to the index finger and represents consequently the Pitta and Kapha doshas of the patient. Pulse can be measured in the superficial, middle, and deep levels thus obtaining more information regarding energy imbalance of the patient.^[11]

In Ayurveda, advocates claim that by taking a pulse examination, imbalances in the three Doshas (Vata, Pitta, and Kapha) can be diagnosed.^[12] The ayurvedic pulse also claims to determine the balance of prana, tejas, and ojas.^[13][11]

Indian Physician taking pulse

In ancient Islamic medicine

Doctor taking woman's pulse. Avicenna's Canon manuscript

Pulse diagnosis, or pulsology, was part of medicine in the medieval Islamic world. The Canon of Medicine, published in 1025, included instructions on how to analyse the pulse and from such examination, physicians considered that they could identify problems ranging from jaundice to dropsy, diphtheria, pregnancy, and anxiety.^[14]

Further reading

• Vasant Lad, Secrets of the Pulse: The Ancient Art of Ayurvedic Pulse Diagnosis, The Ayurvedic Press; 2006 ISBN 1-883725-13-5.
• Mahesh Krishnamurthy, Nadi Pariksha - The Sacred Science of Pulse Diagnosis, Jayanthi Enterprises; 2018 ISBN 978-1-7321901-1-5.
• Bob Flaws, The Secret of Chinese Pulse Diagnosis, 1995 ISBN 978-0-9361856-7-5.