Tradition has produced numerous legends on this subject: the poisonous hand, the blow that kills days later, the pressure point that stops the breath. These tales have their educational value, but they perpetuate a vagueness from which both master and pupil stand to lose everything. Physiology offers sober explanations, sometimes more striking than the myth: a blood vessel bleeding slowly beneath the skull, a nerve reflex that slows the heart, a solid organ that ruptures under a pressure wave. Nothing supernatural, and yet everything corresponds to what the texts say about the body’s vulnerability.

The approach, therefore, is that of the Dao as understood by practitioners: to know the nature of things as they are, ziran, without exaggerating or denying it. Knowing that a body can be seriously injured by a brief, poorly controlled movement is not a lesson in violence; it is the prerequisite for restraint. Those who have understood what their actions can bring about practise song, encounter and contact differently.

The journey follows the body from top to bottom: the head and brain, the neck, the chest, the abdomen and the back, then the limbs. One section is devoted to delayed injuries, which tradition has often mythologised, and the final section to the ethical lessons the masters have drawn from them. This document is intended for study and reflection: it describes medical consequences; it does not teach how to cause them. Any real-life situation involving trauma requires emergency medical attention.

The internal arts distinguish between li—the brute force of muscle—and jin—the cultivated force that flows through a relaxed and structured body. Traumatological medicine expresses the same idea in different terms: what causes injury is not the effort exerted, but the energy actually transmitted to the tissue and the way in which it is dissipated. A blow is not a mass driving inwards; it is a wave that propagates.

First principle: within the bone, this wave takes the form of oscillations that follow the path of least resistance. They converge where the bone thins, and the fracture occurs at the weakest point, sometimes far from the point of impact. A skull, because it is spherical, can thus shatter at a point distant from where the blow was received. The taiji practitioner will recognise a familiar image here: force is revealed by its trajectory, not by the point where it appears to strike.

Second principle: the brain floats in cerebrospinal fluid, enclosed within a rigid bony casing. A sudden acceleration of the head causes it to ‘vibrate’ against its enclosures – a condition clinically termed a concussion – and may rupture the small blood vessels that supply it. The result ranges from brief dizziness to coma and death, depending on the number of vessels affected and their location. This is why the rotation of the head is just as important as the force of the impact.

Third principle: the direction of movement. A target moving towards the blow, or whose head is pulled in the opposite direction, receives considerably greater energy – roughly double, according to the most established clinical observations. The texts speak of ‘borrowing the opponent’s force’; medicine refers to the ‘addition of relative velocities’. In both cases, the effect is not proportional to the effort exerted by the striker.

Fourth principle: tension. A relaxed neck allows the head to lurch forwards, with an increased risk of cervical injury; a muscular and prepared neck stabilises it. Conditioning disciplines such as Jin zhong zhao are specifically designed to enable the body to receive a force without allowing it to penetrate.

Fifth principle, the most important: uncertainty. The same movement can cause a minor bruise or a fatal injury, depending on the angle, the position, the person’s prior state of health, and the phase of their breathing or heart rate. There is no such thing as a perfect strike, and this is what makes any strike morally serious: one never fully controls the outcome. Here, yin and yang come together: the very structure that makes the body resilient also makes it vulnerable.

In internal alchemy, the head houses the Niwan and the upper dantian, the seat of the shen. Medicine regards it as the most precious organ and the least protected against impact: a bony casing, a few millimetres of fluid, and extremely delicate blood vessels. Four examples summarise what clinical practice teaches us.

The temple is the most instructive case. Beneath this thin bone runs the middle meningeal artery, housed in a groove on the inner surface of the skull. A fracture, or even a simple jolt, can pinch or tear it. Blood then accumulates between the bone and the dura mater: this is an extradural haematoma. If the artery is severed, compression occurs rapidly and the outcome is often fatal. If it merely leaks slowly, the victim may appear unharmed for hours, or even days, before headaches, nausea, increasing drowsiness and then coma signal the complication. This is the clearest medical explanation for the ‘delayed deaths’ that legends attribute to a secret of the hand.

The forehead and the bridge of the nose reveal another mechanism. Behind them lie the frontal sinuses, thin-walled cavities, and further down, the cribriform plate of the ethmoid bone, through which the olfactory nerves pass. A fracture extending to this area can tear the dura mater and allow cerebrospinal fluid to leak out through the nose. This clear fluid is sometimes mistaken for a simple runny nose, until severe headaches and the risk of meningitis prompt a visit to the doctor. Loss of the sense of smell, which is also possible, serves as a reminder that one can lose a sense without having experienced a serious injury.

The ear illustrates the fragility of the membranes. An impact that suddenly compresses the air in the ear canal can perforate the eardrum, often accompanied by swelling of the canal and partial or complete hearing loss. The facial nerve, which runs very close by, may be bruised against the edge of the jaw, causing temporary paralysis on one side of the face.

Finally, the jaw serves as a reminder that a serious injury is not always the one that is visible. A fracture of the mandible makes chewing and speaking difficult, and in the event of loss of consciousness, the tongue – detached from its attachments – and broken teeth pose a threat to the airways. A comminuted fracture of the maxilla may also occur some distance from the point of impact, in accordance with the principle of bone oscillations mentioned above. The eye, for its part, cannot withstand any direct pressure: injury to the eyeball leads to what is likely to be permanent blindness, and infection is a complication as serious as shock itself.

One observation runs through all these cases: the severity increases when the head is free to pivot and the neck is relaxed. Trainers who demand a supple yet toned neck, and a gaze that does not fixate, demonstrate through their gestures what neurology illustrates in diagrams.

The neck is the passage through which the ‘dumai’ rises from the spine to the head. Medicine offers a less poetic yet equally striking description: within a diameter of just a few centimetres are concentrated the air, the blood, the spinal cord and the control centres for almost all vital functions. This density explains why almost any injury to this area is both multifaceted and rapid in its effects.

The anterior and lateral surfaces house the carotid sheath, which contains the carotid artery, the internal jugular vein and the vagus nerve. A contusion of the sheath can cause a haematoma that swells with each heartbeat and gradually compresses the trachea. The carotid artery, for its part, contains a pressure receptor at its bifurcation, the carotid sinus: sudden mechanical stimulation can trigger a reflex causing a slowing of the heart rate and a drop in blood pressure, leading to dizziness or even loss of consciousness. The vagus nerve, meanwhile, controls part of the heart’s rhythm and respiration; unilateral damage alone can cause arrhythmias and severe shortness of breath.

The larynx presents the most delicate case. The thyroid cartilage and the cricoid cartilage protect the glottis, and a reflex causing the vocal cords to close – controlled by the laryngeal nerves – prevents any foreign body from entering the airways. A fracture of these cartilages specifically irritates these nerves: the glottis closes spasmodically, air can no longer enter, and the victim suffocates or loses consciousness, sometimes after a deceptive interval. The very protective reaction thus becomes the cause of the danger.

The phrenic nerve, arising from the fourth and fifth cervical nerve roots, controls the diaphragm. A lesion to the spinal cord or to this nerve at the upper cervical level interrupts respiration itself; above the fifth cervical vertebra, the outcome is most often immediately fatal. Below this level, paralysis may be partial or complete depending on the extent of the injury, and is accompanied by neurological shock. Fractured spinous processes, in turn, leave the spinal cord exposed to contusion, even when the bone appears intact.

The posterior aspect corresponds to the cervical spine. A blow to the nape of the neck transmits a shockwave to the brainstem and may cause whiplash, multiple vertebral fractures, intramedullary haemorrhages, or a shock that is fatal in itself due to a sudden disruption of the body’s equilibrium. No amount of muscular effort can reverse what unfolds within a few centimetres.

Jing, qi and shen circulate through this passage; Neidan traditions recommend a straight and free neck, neither rigid nor slumped. Medicine confirms that alignment and mindfulness also offer protection.

The thorax houses the Jianggong, the ‘crimson palace’ of the middle dantian, and it is also the region where tradition places the work of the breath. From a medical perspective, it is a semi-rigid cage that protects two pumps—the heart and the lungs—and which relies on balanced internal pressure to function.

The ribs illustrate the distinction between a minor injury and a serious one. A ‘greenwood’ fracture, where the bone cracks without breaking, causes only pain when breathing. A complete fracture, where the sharp edges tear the pleura, allows air or blood to enter the space surrounding the lung: this is known as a pneumothorax or haemothorax. The lung collapses, and breathing becomes shallow and painful. If the collapse is complete and under tension, the pressure balance is disrupted and the heart itself is pushed towards the opposite side, which can lead to rapid failure. A minor tear in the pleura, on the other hand, often heals by itself.

The diaphragm, the main muscle involved in breathing, reacts dramatically to a blow to the lower ribs or the upper abdomen. A forceful impact triggers a spasm of the diaphragm and the intercostal muscles: the breath is cut off abruptly – this is the familiar sensation of a ‘punch to the solar plexus’. In most cases, normal function returns within a few seconds or minutes. However, when the spasm is severe, or if a bone fragment irritates the diaphragm, mechanical respiratory paralysis can lead to loss of consciousness. The taixi practitioner, who learns to breathe effortlessly and without tension, discovers the value of this reflex within their own body.

The clavicle, the bone connecting the arm to the torso, illustrates the importance of anatomical proximity. A fracture of the clavicle destabilises the shoulder, but the danger lies in what lies beneath it: the subclavian artery and the brachial plexus. A bone fragment may pinch or tear them, leading to paralysis of the arm or ischaemia, which must be resolved within a few hours to prevent gangrene. Deeper down, the sharp edge of the bone may reach the pleural dome and cause a collapsed lung.

One final case is worth mentioning, as it has its own legends: commotio cordis. Documented in athletes, this is a cardiac arrest triggered by a minor blow to the chest, occurring within a very brief window of the cardiac cycle, with no visible injury to either the ribcage or the heart. It is rare, unpredictable, and often fatal without immediate defibrillation. It serves as a reminder that the body does not need to be broken to cease functioning.

The abdomen is the domain of the lower dantian and, at the back, of the Mingmen, the ‘Gate of Life’ situated between the kidneys. This is where tradition places the root of jing. Medicine regards it as a cavity without a protective skeleton, where solid organs, engorged with blood, are held in place by simple ligaments and the tension of the muscular wall.

The solar plexus region, at the junction of the stomach and the spine, contains the liver, gallbladder, pancreas, duodenum and abdominal aorta. A force applied from the front can compress the pancreas and duodenum against the lumbar spine, tear the liver or perforate the stomach. The consequences include peritonitis – that is, irritation of the peritoneum by blood, bile or digestive juices – vomiting, a hard, board-like abdomen, and subsequently haemorrhagic shock. The main difficulty lies in the time lag: the pain may initially seem moderate, and the serious symptoms sometimes only become apparent after forty-eight hours, by which time the victim, already exhausted by blood loss, is no longer able to describe how they feel.

One factor remains little understood: the breathing cycle. During deep inhalation, the abdominal wall relaxes and allows the force to pass through further; during exhalation or when under tension, it absorbs part of it. This is one of the reasons why fitness disciplines such as Jin zhong zhao, which focus on the abdominal wall, the perineum and the diaphragm, produce a measurable protective effect, and why inattention is the body’s greatest weakness.

The spleen is the classic example of a delayed injury. A reservoir of blood situated beneath the lower left ribs, it can rupture silently following an impact, sometimes without any fracture. The tear widens, a haematoma forms beneath its capsule, and rupture occurs several hours, several days, or—more rarely—much later, in the form of a sudden haemorrhage. The surgical literature describes such cases, which are almost always unexpected, and this is what makes them dangerous.

The kidneys, protected by the twelfth rib, are subject to the same mechanisms. A renal contusion causes blood in the urine and lower back pain; a fracture of a lower rib may tear the kidney or its capsule, and displacement may twist the ureter to the point of obstructing the flow of urine, with a risk of infection. It is striking that Chinese medicine locates the reservoir of vital essence in this region: clinical observation confirms the fragility of a site that tradition had already identified as precious.

When full, the bladder behaves like a taut balloon: a blow to the lower abdomen can rupture it and spill urine into the abdominal cavity. Further down, the pubic bone, the inguinal canal and the testicles are both sensitive and fragile; injuries to these areas – particularly hernias or infertility – serve as a reminder that such an injury can be a threat to life itself.

At the back, the thoracic and lumbar spine act as a support structure. A vertebral fracture, a compressed disc or a haemorrhage within the spinal canal causes paralysis below the level of the injury, with loss of bladder and bowel control. Even without a fracture, a nerve may be pinched, and spinal shock may only become apparent later.

The limbs have a more straightforward anatomy, but the risks involved are of a different nature. The bones here are long and strong, and the muscles powerful; what determines the severity of an injury are the structures that run close to the surface: the artery, nerve and vein that cross a joint just a few millimetres from the skin. In the internal arts, the aim of the technique is to open the joints rather than lock them; anatomy supports this requirement, as a joint locked in extension is most vulnerable to rupture.

The forearm and elbow provide the best example. A fracture of the humerus just above the elbow can pinch or sever the median, radial or ulnar nerves, resulting in partial or permanent paralysis of the hand. The brachial artery follows the same path: if it is compressed or torn, the tissues downstream are deprived of blood supply, and surgery must restore circulation within a few hours; otherwise, gangrene and amputation become possible. Hyperextension of the elbow can also tear the biceps tendon or the joint capsules, causing significant swelling and adhesions that permanently restrict movement.

The thigh is the body’s largest muscle mass, and the femur is the strongest bone. However, a violent impact is enough to fracture it or dislocate the femoral head from the hip socket. A fracture results in months of immobilisation and a risk of painful shock. Even without a fracture, a deep contusion can tear the muscle sheath and cause an intramuscular haematoma, resulting in a painful, long-lasting lump where muscle fibres herniate through the torn fascia.

The knee can only withstand minimal lateral stress. A blow from behind, whilst the leg is bearing the body’s weight, can tear the ligaments, dislocate the joint, or fracture the patella under the tension of the quadriceps. The artery, vein and nerve of the leg pass through the popliteal fossa: damage to these puts blood supply to the foot at risk. Finally, the tibia, lacking muscle mass to protect it, is vulnerable to direct fracture, and the Achilles tendon can rupture under sudden traction, resulting in the loss of the ability to walk.

A key lesson emerges from these observations: injuries to the limbs appear less serious because they do not pose an immediate threat to life. Yet they leave lasting sequelae, on a scale that alters a person’s life. A responsible clinician takes this into account just as much as life-threatening conditions.

Medicine is well acquainted with the ‘lull’, that moment when a seriously injured person appears to be doing well before their condition deteriorates. This phenomenon is the most plausible explanation for accounts of fatal blows whose effects only become apparent hours or days later. There is no secret or mysterious technique involved: it is a matter of blood vessels bleeding slowly within an enclosed space, or organs whose walls gradually give way.

These timeframes are orders of magnitude, not hard and fast rules. What remains constant is a keen sense of observation: a severe shock is never ‘over’ the moment the pain subsides.

Shock, in the medical sense, adds another dimension. It is the collapse of circulation when the body loses too much blood or the nervous system is overwhelmed: the skin becomes pale and clammy, the pulse rapid and weak, and consciousness wavers. It can occur without any apparent injury, and the body can sometimes succumb to it on its own. Tradition speaks of an imbalance between yin and yang; physiology of a disruption of homeostasis; both describe the same reality.

This leads to a course of action that is a matter of common sense: after any significant blow to the head, neck, chest or abdomen, the person must be monitored, not left alone, and emergency services must be called as soon as any of the above signs appear, even if they do so later on. No reputation for resilience exempts one from this precaution.

All of the above leads to a conclusion that the masters had already drawn from experience: knowing what an action can bring about changes the way it is carried out. ‘De’, virtue understood as effective power, is not a moral quality added to technique; it is the measure that enables it to be exercised without causing harm. The precepts, ‘jie’, which a disciple receives as part of the transmission, serve this function first and foremost: to set a limit where the capacity to act exceeds the capacity to foresee.

The primary reason for this limit is uncertainty, as already mentioned. An identical blow may result in a minor injury or a fatal outcome depending on factors beyond anyone’s control: age, pre-existing frailty, the exact position of the body, or the ground onto which the person falls. Even the most experienced practitioner cannot gauge the severity of a strike in the space of a fraction of a second. To strike, therefore, is always to accept that one cannot control the consequence, and wuwei, or non-action, takes on a very concrete meaning here: not acting when the action exceeds what one can guarantee.

The second reason is legal and moral responsibility. The law judges the consequences of an action as much as its intention, and self-defence presupposes a response proportionate to the attack. A permanent injury or death, even if caused by someone acting in self-defence, leaves its mark on the lives of both individuals. Martial traditions have often expressed this through the figure of the master who does not fight, not out of weakness, but because he knows the cost of a fight.

The third reason lies in the very nature of the internal arts. They cultivate stillness, tranquillity, stability and contemplation: qualities that sharpen perception and make movements more measured. An art that leads to a greater awareness of another person’s body also leads to a greater awareness of their vulnerability, and thus to a reduced desire to harm them. It is in this sense that one might say that medical knowledge is a form of ziran: seeing things as they are.
A practical responsibility accompanies this knowledge: knowing how to provide first aid. In the event of a serious injury, the first course of action is to call the emergency services without delay, not to move the neck of a person who has suffered a blow to the head or neck, to clear the airways, to control bleeding by direct pressure, to place an unconscious person who is breathing in the recovery position, and to monitor their breathing and level of consciousness until the emergency services arrive. This skill forms part of what a Master who cares for their pupils must teach.

Modern medicine and Taoist internal arts agree on one point: the human body is both robust and extremely fragile, and what protects it best is neither strength nor hardness, but the quality of its structure, its breath and its awareness. The examples reviewed—the slow bleeding beneath the temple, the larynx closing up, the spleen failing after several days, the heart stopping from a minor blow—show that the legends of the ‘poison hand’ are based on real phenomena, but that they can be explained without resorting to mystery.

This knowledge is only valuable insofar as it is put to good use. It can foster restraint, prudence and a desire to help, or the vanity of supposed power. The masters of the Dao have always preferred the former path: cultivating jing, qi and shen, so that life—their own as well as that of others—may be preserved rather than destroyed.

There will be a course on vital points in early 2027, linked to natural boxing, for those who have practised the fa jin of Ziran Men.