Modern Interpretation of Meridians

“Modern interpretation of meridians” has long been a topic of heated debate between traditional TCM practitioners and modern TCM practitioners. Here, traditional TCM practitioners refers to those who don’t have enough knowledge of modern medicine, believe that TCM doctors need not study modern medicine, oppose modern scientific research on TCM, and refuse to accept interpretation of meridians with modern medicine; while modern TCM practitioners refer to those who not only studied traditional TCM but also have background of  modern medical research, keeping up with contemporary anatomy, physiology, pathology, and pharmacology.

The author has previously introduced acupuncture definition of meridians. As a modern TCM practitioner, now I am introducing the modern interpretations of meridians.

Meridians are one of the most fascinating yet challenging areas in the modernization of TCM research.

At present, the scientific community has not identified any independent anatomical structure that perfectly corresponds to the classical descriptions of meridians. Therefore, the “modern interpretation of meridians” is better understood as a collection of multidimensional scientific hypotheses, each attempting to explain the nature of meridians and the scientific principles behind them from different perspectives.

The following are several mainstream modern scientific explanations and research directions:

1. The Neuro–Endocrine–Immune Network Theory (the most mainstream explanation)

This is currently the most widely accepted theory. It suggests that the functions of meridians overlap extensively with the known regulatory networks of the nervous, endocrine, and immune systems.

Relation to the nervous system:

• Many meridian pathways closely resemble the distribution of peripheral nerves (e.g., the Pericardium Meridian of Hand–Jueyin parallels the median nerve).

• Acupoints are often located where nerve endings, bundles, or branches converge.

• The “Deqi” sensation of acupuncture (soreness, numbness, heaviness, or distension) is primarily triggered by stimulating deep sensory receptors and nerve fibers.

• The transmission effects of meridians can be explained by neural reflexes (e.g., somato–visceral reflexes, where stimulation of acupoints on the body surface affects visceral function via the nervous system).

  
  

  Reference: Liang J. Study on the Central Neural Pathways Connecting the Brain and Peripheral Acupoints Using Neural Tracers. CNS Neurosci Ther. 2025 Aug; 31(8): e70554. doi: 10.1111/cns.70554. PMID: 40762123.

  Abstract: Recent advances in neuroanatomy and functional neuroimaging provide empirical support for the complex connections between peripheral sensory structures and central nervous networks. Studies show that stimulating specific acupoints can activate afferent neural pathways, thereby regulating brain regions such as the thalamus, somatosensory cortex, limbic system, and autonomic centers in the brain stem. For example, fMRI studies have found that acupuncture at ST36 (Zu-san-li) and LI4 (He-gu) activates the hypothalamus and nucleus accumbent while suppressing activity in the anterior cingulate cortex, amygdala, and hippocampal complex.

  
  

Relation to the endocrine and immune systems:

• Acupuncture signals transmitted through the nervous system reach the central nervous system (brain and spinal cord), modulating the hypothalamic–pituitary axis and releasing various hormones (e.g., endorphins, natural analgesics), thereby achieving systemic regulation.

• Studies confirm that acupuncture can modulate the activity of immune cells such as lymphocytes and macrophages, explaining its anti-inflammatory and immune-enhancing effects.

This theory holds that meridians are not an unknown, unique anatomical structure but rather an intuitive, holistic description of the body’s regulatory systems by ancient physicians. In modern medical terms, this regulatory system is the neuro–endocrine–immune network.

2. The Connective Tissue/Fascia Theory

This theory has gained increasing attention in recent years. Studies show that many acupoints and meridian pathways are located in fascia, particularly in planes rich in loose connective tissue. Fascia is a continuous body-wide network, providing structural support for the idea of meridians as “channels.”

• Fascia is rich in nerves, blood vessels, lymphatic vessels, and sensory receptors. Acupuncture within fascia generates strong biomechanical and electrical signals, which can be transmitted through this network and influence physiological functions at distant sites.

• Evidence: Anatomical studies reveal that about 80% of acupoints coincide with “connective tissue convergence points” within fascia.

Conclusion: The fascia network may serve as one of the biological structural bases of meridians, functioning as the “material conduit” for signal transmission, with nerves and blood vessels acting as “functional components” within the conduit.

3. The Low Hydraulic Resistance Channels and Interstitial Fluid Transport Theory

Modern Interpretation of Meridians

Some studies using physical methods have discovered that tissues along meridian pathways exhibit lower hydraulic resistance (resistance to fluid flow), which may facilitate the movement of interstitial fluid (the fluid between cells) and the transport of certain chemical substances.

• Evidence: Using radioactive isotope tracers, scientists found that tracers injected into acupoints diffuse preferentially along meridian pathways rather than spreading evenly in all directions.

Conclusion: These low-resistance channels may serve as “highways” for the transport of bioactive substances such as hormones and cytokines. This provides a modern biophysical perspective for the classical idea of “qi and blood circulation,” where “qi” may partly represent the flow of information and substances within these channels.

4. The Bioelectromagnetic and Energy-Information Theory

This hypothesis proposes that meridians are preferential pathways for bioelectric and electromagnetic signals in the human body.

• Evidence: The electrical resistance of acupoints differs from surrounding tissues (acupoints are often low-resistance sites).

• The human body naturally generates bioelectric and electromagnetic fields, and meridian pathways correlate to some extent with their distribution.

• Acupuncture can alter local and systemic electromagnetic fields, thereby influencing cellular function.

  
  

Conclusion: This theory interprets “qi” partly as the flow of bioenergy (electricity, magnetism, light), with meridians functioning as “circuits” that direct and concentrate these energies.

Summary

Classical Chinese Medicine Concepts – Possible Modern Medical Correlates and Interpretations

·       Meridians (Jing-luo): A functional regulatory system whose anatomical basis may involve neural networks, fascial connective tissue, and low-resistance fluid channels, rather than a single physical conduit.

·       Qi and Blood: The flow of information, energy, and material substances. This includes neural signals, hormones, immune factors, interstitial fluid, and bioelectric activity.

·       Acupoints: Sensitive sites or amplifiers of function. These are specialized regions rich in nerve endings, blood vessels, lymphatic vessels, and fascial receptors, where stimulation can efficiently regulate systemic functions.

·       Mechanism of Acupuncture: Physical stimulation (needling) activates the neuro–endocrine–immune network within the body, triggering a series of self-regulatory and reparative responses (such as analgesia, anti-inflammation, and correction of functional disorders).

Current Scientific Consensus:

The essence of the meridian system is likely a complex functional regulatory network formed through the interaction and integration of known anatomical structures (nerves, fascia, blood vessels, etc.), in ways not yet fully understood. Ancient physicians, through long-term clinical observation and practice, summarized the operating principles of this system (i.e., meridian theory). Modern science, using its own language and methodology, is gradually verifying and elucidating its scientific basis.

This does not negate the existence of meridians; rather, it provides a more solid modern biological foundation, demonstrating the forward-looking wisdom of traditional Chinese medicine theory.