SENSE OF PAIN

There is a special set of nerves and sense organs for touch. There is another set for heat, one for cold, and still another set for pain. Some years ago when physicians did not make many blood examinations they took the blood from the lobe of the ear. Now that they make many, they have found the tip of the finger a much more convenient place to prick and, with the pragmatical philosophy of the human race, they say that the blood in the finger is better than that in the ear. Personal experience with both operations has demonstrated to me the disagreeable disadvantage of trifling with pain organs in the finger tips. The existence in the same area of both touch and pain organs may be a cause of considerable trouble when an operation is attempted under local anesthesia. You can explain to an intelligent, well-balanced patient that you will cause no pain but that nevertheless the sense of touch will still be present. Some uncooperative patients, highly nervous, just cannot make this differentiation. Beset with fear, they jump or cry out at every touch. The smart surgeon will be the one to quit under these circumstances and call the anesthetist to put the patient to sleep and remove the mental impediment.

Although the sense of touch is almost always fairly accurately localized, this is not necessarily at all the case with pain. One reason is the enormous number of pain organs. The numbers of touch and pain organs in the skin are 500,000 and 4,000,000, respectively. In the old days when the teeth were not so carefully attended to, it was often difficult for the patient to tell which tooth was aching. It might seem to him that the whole jaw was involved. The dentist might have to rely on his own examination. Despite the extreme sensitivity of the front of the eyeball who can tell where a cinder is resting?

One of the few surgical writings which might be considered classic is John Hilton's Rest and Pain, written nearly a century ago. His full phrase was "The Diagnostic Value of Pain" and he showed how careful we must be to interpret pain correctly, with knowledge of anatomy; and particularly how the anatomy had developed through the ages.

Hilton cited for his first case a man with pain in his ear. Examination showed that he had a jagged tooth and an ulcer opposite it on the side of his tongue. When these were attended to, the pain in his ear ceased. The fifth or trifacial nerve furnishes sensation at both these places and it is rather common for disease in the mouth to send pain shooting up to the ear. Mr. Hilton found that when a joint was inflamed, the pain might be felt over the muscles that moved the joint, rather than over the joint itself.

The pain of appendicitis usually starts in the mid-upper abdomen, rather than over the appendix. One of our local surgeons used to say, "If the pain starts in the right lower abdomen, it is not appendicitis." Patients with gall bladder disease are likely to experience pain in the right shoulder. Disease of the spine often gives pain in the front belly. In fact, although pain is given us as a protective blessing, and not to mortify us or as retribution for what Great-grandmother Eve did, its tendency to masquerade often makes the task of the diagnostician far from easy.