EASTOVER BLOG

Here is a detailed explanation of how pathogens invade the human body, specifically concerning the exterior-interior (表里 biǎo-lǐ) progression and the role of fascia/membranes (筋膜 jīnmó), from the perspective of Traditional Chinese Medicine (TCM).

Overview: The Pathway of Pathogenic Invasion (From Exterior to Interior)

TCM views the human body as an integrated whole, internally connected by a system of Meridians (经络 jīngluò) and externally protected by Defensive Qi (卫气 Wèi Qì) and the striae and interstices (腠理 còulǐ)—the pores and microscopic spaces between the skin and muscles.

Pathogenic factors (like Wind, Cold, Summer-Heat, Dampness, Dryness, and Fire, known as the “Six Excesses”) typically invade the body along a predictable, deepening pathway:

Skin & Body Hair (Exterior) → Luo-Collaterals → Main Meridians → Fascia/Muscles → Six Fu-Organs → Five Zang-Organs (Interior)

In this process, Fascia (筋膜 jīnmó) acts as a critical conduit and pivot point where pathogens often lodge and manifest.

Step-by-Step Breakdown of the Invasion Process

1. Initial Stage: Pathogen Attacks the Exterior (Exterior Syndrome)

• Pathway: The pathogen (e.g., Wind-Cold) first assaults the body’s outermost defenses—the Defensive Qi (Wei Qi) and the skin and pores.
• Manifestations: The body’s righteous Qi (Zheng Qi) rallies to fight the invader at the surface. This battle results in classic “Exterior Syndrome” symptoms: aversion to cold, fever, headache, stuffy/runny nose, and a floating pulse (浮脉 fú mài).
• The Crux: If the body’s Qi is strong or treatment (like inducing sweat to release the exterior) is applied promptly, the pathogen can be expelled completely. This is the optimal window for treatment, encapsulated in the axiom: “The superior physician treats the disease when it is in the skin.”

2. Intermediate Stage: Transmission into Meridians and Fascia (The Transition Zone)

If the exterior syndrome is not resolved, the pathogen penetrates deeper through the meridian system. This is where the concept of “Fascia” becomes central.

• What is “Fascia” (筋膜 Jīnmó) in TCM?
  • It is a broader concept than the anatomical fascia of Western medicine. It encompasses all membranous, net-like, and束约束缚 (shùfù – binding) structures that wrap, connect, and support the muscles, bones, and organs. It is governed by the Liver (肝 Gān), which “controls the tendons and fascia” (肝主筋 Gān zhǔ jīn).
  • The spaces between the skin and muscles (striae and interstices – 腠理 còulǐ) are part of this fascial network.
• How Do Pathogens Invade the Fascia?

• Via the Meridians: Pathogens move from the skin into the Luo-Connecting vessels and then into the larger Main Meridians. Meridians transport Qi and Blood, but they can also transport pathogens. The Qi of the meridians spreads to the tendons and fascia they govern, carrying the pathogen with it.
• Direct Invasion: Certain pathogens, particularly Dampness (湿 shī) and Wind (风 fēng), have a tendency to “attack the voids” and creep into the spaces within the fascial network.
  • Example: Invasion of Wind-Cold-Damp into the fascia obstructs the smooth flow of Qi and Blood, causing pain, Bi Syndrome (痹证 bì zhèng – painful obstruction), rheumatism, muscle aches, and cramping/stiffness (拘挛 jū luán). The pain may be wandering (characteristic of Wind), heavy and sore (characteristic of Dampness), or worse with cold (characteristic of Cold).
• Manifestations: Exterior symptoms may linger, but deeper symptoms emerge, such as generalized muscle and joint soreness, stiff neck and back, and overall bodily discomfort. This represents a “half-exterior, half-interior” stage.

3. Advanced Stage: Pathogen Afflicts the Six Fu-Organs (Early Interior Syndrome)

Breaching the meridian and fascial layers, the pathogen moves inward to the Six Fu-Organs (胃 Wèi – Stomach, 大肠 Dàcháng – Large Intestine, etc.). These organs are “hollow” and their function is to “transport and transform” – they are meant to be free-flowing.

• Pathway: Often follows the internal-external relationships between meridians and their paired organs. For instance, Cold in the Taiyang (Bladder) Meridian can transmit to the Bladder Organ itself.
• Manifestations: Dysfunction of the specific Fu-organ occurs:
  • In the Stomach: Epigastric distension, pain, nausea, vomiting.
  • In the Large Intestine: Abdominal pain, diarrhea, or constipation.
  • In the Gallbladder: Hypochondriac pain, bitter taste in the mouth, jaundice.

4. Critical Stage: Pathogen Settles in the Five Zang-Organs (Deep Interior Syndrome)

This is the most severe stage, where the pathogen damages the core of the body—the Five Zang-Organs (心 Xīn – Heart, 肝 Gān – Liver, etc.). These organs store vital essence and govern mental-spiritual aspects; their damage signifies serious illness.

• Pathway:
  1. From a Fu-organ to its internally-externally related Zang-organ. For example phlegm around Pericardium cause pain penetrating behind the shoulder blade.
  2. A severe pathogen may “perversely transmit” directly to a vital center (e.g., high fever causing delirium and coma by “invading the Pericardium”).
  3. Internal generation of pathogens due to emotional stress, diet, or overwork, which directly injure the Zang-organs.
• Manifestations: Severe dysfunction related to the essence, blood, fluids, and spirit:

• In the Heart: Palpitations, chest pain, pain under shoulder blade, insomnia, even loss of consciousness.
• In the Liver: Severe hypochondriac pain, dizziness, tremors, convulsions, wind-stroke – like Parkinson’s.
• In the Spleen: Profound fatigue, emaciation, edema, bleeding disorders.
• In the Lungs: Violent coughing, wheezing, coughing blood.
• In the Kidneys: Low back pain, knee weakness, impotence, infertility, severe chills or night sweats.

Summary and Analogy

Think of the human body as a fortified city:

• Skin & Pores: The city walls and gates (first line of defense).
• Meridians: The main highways and roads inside the city.
• Fascia/Interstices: The alleys, sewers, and spaces between buildings where enemies can hide and cause localized trouble.
• Six Fu-Organs: The marketplaces, warehouses, and public squares (functional centers).
• Five Zang-Organs: The central palace and government headquarters (command centers).

Pathogenic invasion is the process of: Breaching the gates (Exterior Syndrome) → Traveling along the main roads (Meridians) → Hiding in the alleys and disrupting neighborhoods (Fascia, causing pain) → Sabotaging the markets (Fu-Organs) → Finally storming the palace (Zang-Organs).

Therefore, the core principles of TCM treatment and health preservation are to:

1. Strengthen the Defensive Qi (fortify the walls).
2. Expel the pathogen as soon as it is at the exterior (guard the gates).
3. Ensure the free flow of Qi and Blood in the meridians and fascia (keep the roads and alleys clear) through acupuncture, massage, and exercise, so pathogens have no place to lodge.
4. Tonify and regulate the internal organs so the “palace” is strong and resistant to attack.

1. The Injury Creates the “Void” or “Breach”

In TCM, the body’s first and most important line of defense is the Wei Qi (Defensive Qi). This Qi flows on the surface of the body, warming the skin and muscles, and controlling the opening and closing of the pores (腠理 còulǐ – the striae and interstices).

• An injury—be it a cut, sprain, bruise, or even a surgical incision—creates a localized physical breach in this defensive barrier.
• This breach is not just physical. The trauma disrupts and weakens the normal flow of Qi and Blood in that specific area. Think of it as a local power outage in the body’s security system.
• This area of stagnated Qi and Blood (气滞血瘀 qì zhì xuè yū) and weakened Wei Qi becomes a “perfect void”—a point of low resistance.

2. Why Dampness and Cold Are Drawn to This Void

The properties of Cold and Dampness make them particularly suited to exploiting this weakness:

• Cold (寒 Hán): Its nature is contracting, congealing, and obstructing. It seeks out areas of weakness where it can settle, cause stagnation, and slow down all metabolic and circulatory processes. An injured area with already impaired circulation is an ideal target. Cold will worsen the pain and stiffness (e.g., making an old sprain ache in cold weather).
• Dampness (湿 Shī): Its nature is heavy, turbid, sticky, and “yin” in nature. It tends to sink downward and to seep into cavities and weak spots. An injury site is a magnet for Dampness because:
  • It’s a physical depression or area of stagnation.
  • The impaired Qi (which normally transforms and transports fluids) cannot handle moisture properly, leading to an accumulation of pathological Dampness right there.

3. The Consequence: A Vicious Cycle of “Painful Obstruction” (Bi Syndrome 痹证)

When Cold and Dampness invade an unattended injury, they don’t just cause temporary discomfort. They lodge themselves in the tissues—particularly in the fascia, tendons, muscles, and joints.

This creates a condition known as Bi Syndrome (痹证 Bì Zhèng)—often translated as painful obstruction syndrome.

• The pathogen obstructs the meridians and collaterals.
• This prevents the smooth flow of Qi and Blood.
• The classical result is pain, numbness, heaviness, and swelling.
  • “The pain is due to the obstruction; if there is free flow, there is no pain.” (不通则痛，通则不痛 bù tōng zé tòng, tōng zé bù tòng)

Because these pathogens are “sticky” and persistent, the condition often becomes chronic. The original minor injury may have long healed, but the patient is left with a persistent, weather-sensitive ache or stiffness in that area—a clear sign that Cold and/or Dampness have taken up residence.

Clinical Example & Analogy

• Example: Someone sprains their ankle. They ice it initially (which is a Cold invasion in itself from a TCM view) but never fully rehabilitate it with movement, heat, or acupuncture to restore strong Qi and Blood flow. Years later, that ankle becomes their “barometer,” aching and feeling stiff with every change in the weather, especially on cold, damp days. The void was created and never properly sealed.
• Analogy: Think of an unattended injury like a small, unnoticed crack in the foundation of a house.
  • Cold is like the frost that gets into that crack, freezes the moisture inside, and expands the crack, making it worse.
  • Dampness is like the rainwater that seeps through that crack, leading to mold, rot, and a musty, heavy feeling in the basement.
  • Together, they create a chronic, deeply rooted problem that is much harder to fix than the original crack.

TCM Treatment Principle

The treatment logic follows directly from this understanding:

1. Expel the Pathogens: Use acupuncture, moxibustion (especially effective for Cold), and herbs to disperse Cold (散寒 sàn hán) and resolve Dampness (祛湿 qū shī).
2. Restore Flow: Use techniques to invigorate Blood (活血 huó xuè) and move Qi (行气 xíng qì) to break up the stagnation in the affected area.
3. Strengthen the Body: Ultimately, tonify the Wei Qi and the underlying Zheng Qi (Righteous Qi) to “seal the void” and prevent re-invasion.