Mystery and Excellence of the Human Body

Pain

In the 1850's, the Scottish explorer David Livingstone described his feelings when a lion attacked him: "He caught my shoulder as he sprang, and we both came to the ground.... Growling horribly close to my ear, he shook me as a terrier does a rat. The shock... caused a sort of dreaminess in which there was no sense of pain nor feeling of terror."

Livingstone's reaction was not unlike that of soldiers observed a century later in World War II. Field surgeons often marvelled at the fortitude of the many badly wounded men. At first, doctors theorized that the soldiers seemed oblivious to pain simply because they were glad to be alive. But many years — and scientific experiments — later, pain specialists came to recognize that Livingstone and the young soldiers were experiencing what is now called stress-induced analgesia: pain relief that results from extreme stress. The explanation for this phenomenon is that the brain at times manufactures its own opiates. These pain relievers and mood elevators, the endorphins and enkephalins, are similar to morphine, only much more powerful.

Under normal circumstances, however, the human body is all toosusceptible to pain. Pain is the price man pays for his extremely complex biological system; its function is to alert the body to damage to its tissue.

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How does pain work? If you accidentally touch a hot stove, your hand will be well away from it before you realize why you didn't pick up the kettle after all. A danger signal has shot up nerve pathways in the arm and into the spinal corde. The sensory channels of the spinal cord transmit the message to the brain. At the same time, another message is going back down the motor channels which run from the spinal cord to the muscles: "Take evasive action!" The body cannot afford to waste a fraction of a second, so immediate is the threat.

This automatic sequence of perception and reaction is known as a reflex arc and there are thousands of such arcs all over the body. Pain therefore is a necessary protective mechanism, yet it is hardly a reliable guide. Many dangerous tumors, for instance, cause no pain at all until the damage done to the body is beyond repair. It is now generally accepted that while pain from the skin, muscles, joints and tendons travel through the central nervous system, pain arising from the viscera (internal organs) is conveyed by the autonomic nervous system, a much less effective system. The viscera have few nerve fibers, and lack access to the sophisticated interpreter faculties in the brain. Pain from the viscera can be located only in a vague and imprecise way. When the brain is unable to place pain accurately, it tends to "make do" with the nearest point from which it has experienced pain before. In this way, visceral pain arising beneath an old scar will seem to be coming from the scar itself.

Another freakish manifestation of pain is the phenomenon of the "phantom limb", which may follow amputation. The limb is felt to be there, and may appear to become shorter and shorter as time passes, until a man who has lost an arm may feel as if his hand is sprouting from his shoulder. This phenomenon is still not well understood, but it is thought that some parts of the body are very richly represented in the brain and therefore not easy to "forget". In the above example, it seems that the severed nerve trunks in the shoulder can still transmit pain signals to the brain. The brain interprets these as coming from the arm and hand which the nerves used to serve. The arm is gradually "forgotten", while the "memory" of the highly sensitive hand and fingers lingers on.

Since earliest times men have tried to alleviate pain. Hundreds of years ago, Arab doctors hit on the idea of anesthetizing a patient's arm by packing it in snow. And for at least 2500 years, Chinese acupuncturists have been inserting fine needles into the body at certain precise

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points to bring relief from illness and pain. In modem times, allopathic doctors use a huge variety of anaesthetics, usually injected close to the affected area. General anaesthetics, by contrast, are used to put much of the nervous system out of action, and prevent the brain from perceiving pain. Until recently, most people assumed that an anesthetized person was unconscious and had no idea what was going on. That is no longer a safe assumption. Researchers have discovered that unconscious patients can hear. As a result, a casual remark by the surgeon in the operative room can have a strong impact on the patient and affect his chances of recovery.

In pharmaceutical companies the world over an intensive search is going on for the perfect pain reliever. But because so many pain relieving drugs have undesirable side effects, notably addiction, there is a corresponding trend nowadays to look for safer ways to help people control pain. This includes relaxation, meditation, psychotherapy, hypnosis, and the age-old practice of acupuncture.

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After great pain a formal feeling comes

After great pain a formal feeling comes —

The nerves sit ceremonious, like tombs;

The stiff Heart questions — was it He that bore?

And yesterday — or centuries before?

The feet, mechanical, go round

A wooden way

Of ground, or air, or ought,

Regardless grown,

A quartz contentment, like a stone.

This is the hour of lead

Remembered if outlived,

As freezing persons recollect the snow —

First chill, then stupor, then the letting go.

Emily Dickinson 1830 — 1886

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