WHAT CHEMICAL PROCESS MAKES MUSCLE FUNCTION
We see an insect like a dragon fly poised in mid-air. Its wings beat so rapidly that they are invisiblemere blurs. It must take a lot of sugar and oxygen to allow muscles to function that rapidly without fatigue. The insect’s muscle is just like the human muscle, at least in this, that unless it is supplied with materials, fatigue accumulates until it has to stop.
And largely this means oxygen. If a muscle, even a human muscle, has plenty of oxygen supply, it can work indefinitely.
The insect’s muscles are so much more efficient comparatively than human muscles because air is carried directly from the surface of the insect body to the internal organs by a set of little tubes. Each muscle fiber has its own little pipeline bringing it all the oxygen it needs.
The higher animals, including ourselves, have the same thing, but by a much more complex and less efficient arrangement. Like the insect, we get our oxygen from the air. But the oxygen is not carried to the muscle fiber direct. True, it goes there, as does the insect’s, in little tubes; but in the case of the human body they are blood vessels, and the oxygen is carried to the muscle by the red blood cells. But, as in the case of the insect, each human muscle has a tiny, individual pipeline or capillary running beside it; its walls are so thin that the oxygen in the blood can readily pass over to the muscle.
INTERESTING CHEMICAL FUNCTION
This oxygen-carrying capacity of the blood is one of the most interesting chemical functions of the body. It was known to one of the earliest investigators in physiology, Mayow, that dark blood from a vein, when exposed to air and whipped, will turn bright red. And his contemporary, Richard Lower, showed that exactly the same change takes place in the dark blood from the right side of the heart when it passes through the lungs. Because in the lungs it passes through such thin-walled vessels that it is practically exposed to the air and picks up oxygen.
The chemical substance in the blood which does this is called “hemoglobin,” and is a part of the red blood cell. When exposed to oxygen at atmospheric pressure, hemoglobin will take up oxygen, forming a loose chemical combination called “oxy-hemoglobin.” When this is put into a vacuum, it again gives up its oxygen. More or less, that is the way in which the interchange occurs in the body. In the lungs, hemoglobin is exposed to air at atmospheric pressure, and while there is nowhere exactly a vacuum in the body, conditions in the muscle approximate a partial vacuum.
The essential nature of the chemical changes in this vital function of oxygen carriage revolve around the properties of iron, which is a constituent of hemoglobin. Iron, which is thus so necessary to animal life, is carefully conserved in the body. Every infant has a good supply of body iron at birth. But as there is little, or none, in milk, it has to be supplied beginning at about the age of six months. Hence the importance of the pigment foods in infancyyolk of egg, spinach, etc.
MUSCLE TEARS ARE COMMON AND SHOULD BE TREATED
A person slips on the ice or starts to fall, holds himself straight with considerable effort, and at that instant feels a violent pain in the leg. Sometimes the pain is so severe that he falls in spite of his efforts to keep erect. Sometimes he manages to go on, but the pain in the leg persists.
Most frequently the pain is in the muscles of the calf, but almost equally as frequently it is in or around the knee.
What has happened? Well, in the absence of a broken bone or a sprain of the tendons or a dislocation, the chances are that there has been a tear of the muscles. These muscle tears are far commoner than we have thought. They may occur in any muscle of the body, simply with a violent effort and the muscle taut.
For instance, the baseball pitcher’s “glass arm” usually is due to a rupture of one of the muscles of the arm. The “Charlie horse” of the football player also is often a muscle rupture.
The sheath of the muscle tears, and the belly of the muscle can be seen protruding out from it, causing a bulge or deformity when the muscle is tensed.
Of the places where the muscles tear, the calf muscles come first in frequency, then the big muscle in the front of the leg, then the biceps of the arm, and then the ball of the thumb. The calf muscles can be torn by a fall in which the foot is twisted. The tear usually occurs just at the narrow bottom part of the muscle toward the heel.
The muscles of the leg are tom so frequently because the knee-cap is a peculiarly delicate and exposed bone. The knee-cap is held in place partly by a sort of peninsula coming out from the bone of the thigh. When this peninsula is not long enough to keep the knee-cap in place, people suffer what is called chronic recurrent dislocation of the knee-cap.
The treatment usually employed, which was invented by a Liver-pool surgeon, is to hit the outside of the thigh bone with a hammer until the reaction and irritation cause the peninsula to form.
These conditions may become quite crippling, and so severe as to require a surgical operation for their repair. They are often allowed to run along entirely too long. The patient first tries to rub them out, or bathe them out, and then he has a rubber rub them. Finally, maybe somebody straps him up or puts a plaster of Paris cast on him all of which is useless or even harmful in treatment.
Slight tears will heal if given enough rest, and in the course of time most of them will heal if the injured person “toughs it out,” to use a phrase I heard the other day from a person who had a headache. But in a small group of cases nothing does any good until the tear in the muscle envelope is sewed up, and this can only be done by a surgical operation. Those who have temporized along with injuries of this kind should consider the possibility of a muscle tear, and have it attended to properly.
“TENNIS ELBOW” IS CAUSED BY STRAIN, Do NOT NEGLECT
Several years ago a surgeon in Boston, who was an extremely enthusiastic tennis player, found that he was unable to continue playing tennis because of pain on the outer side of the elbow. The pain was located in a small spot just where one can feel the bone on the outer side of the elbow. It hurt especially when the doctor tried to do such things as take hold of a glass of water. He could hardly hold the glass firmly long enough to get it to his mouth. Naturally he could not play tennis any more because grasping the racquet was impossible.
He thought at first it was a small fracture or chip off the bone, but several x-rays taken in many positions failed to show any such disease. Finally, after several weeks of trying to get better with mild treatments, he decided to have it opened up surgically. One of his friends did the work for him and it was done under local anaesthesia. He insisted on this so that he could look into the joint himself. The only thing that was found was chronic inflammation with a thickened bursa just under the insertion of the extensor carpi radialis longior muscle. This bursa was removed and the patient recovered.
During his convalescence he found a number of people who had had the same thing, and described it under the name of “tennis elbow.” Tennis elbow is due to strain and chronic irritation at the point mentioned, because in grasping the racquet this muscle is put upon tension, and as it moves back and forth over the surfaces above the joint, it may pull the tissues and rub the tissues so that a chronic inflammation results.
The symptoms are characteristic, with localized pain and inability to grasp objects firmly with the hand. Treatment is usually satisfactory without resorting to the radical operative procedure to which the surgeon mentioned,, submitted himself. Heat, rest, strapping with adhesive tape, sometimes putting on a plaster cast, and later on when pain is not so severe, massage, will usually clear up most cases.
One of the most important things about the condition, no matter how acquired, is that it should not be disregarded. Especially it should not be called “just a little rheumatism,” and an attempt made to drive the rheumatism away by exercise, manipulation, etc. To continue to play golf or tennis after having acquired an athlete’s elbow is to court permanent crippling.
BEAUTIFUL WAY If WHICH BONES, JOINTS Do WORK
If we discuss the body as a machine, it is not difficult to see just what the function of the muscles is. These, of course, are to the body merely what the engine of an automobile is to the automobile. In order to make the automobile move and do work, other structures are necessary. So it is with the body.
These other structures, are, first, the nervous system and, second, the bones and joints. While the muscular contraction is largely an example of the conversion of chemical energy into mechanical energy, there is also an electrical factor in it which is supplied by the nervous system. At least, so far as we know anything about it, the nervous impulse is an example of electrical energy. The only thing that has been found to be present in a muscle or nerve preparation at the moment of contraction is the change in electrical potential. The most important artificial means we have of stimulating a nerve, and hence a muscle, is an electrical shock.
In our comparison to the automobile, the nervous impulse is represented by the spark from the battery.
The other element in the body as a machine is represented by the bones and joints, which may be compared to the framework and wheels of an automobile. Nothing in nature is really more beautiful than the manner in which the bones are constructed to do their work. They have been, in fact, the model of the best sort of engineering construction.
In other words, they combine lightness and strength in their construction. A long bone is a hollow tube with an extremely strong, thick, compact mass of bone at the cortex enclosing air cavities and a fine network of bony structure, which makes for lightness. If all of our bones were solid bone a man would weigh two or three times as much as he actually does, and would not gain anything in efficiency from the standpoint of tensile strength. Inside the bone, of course, is also the marrow, but this has nothing to do with the functions of the bone itself.
Equally amazing are the joints, and upon one or the other of these joints has been modeled every sort of hinge or ball and socket joint used in mechanical construction. Indeed, on an old Egyptian wall painting there was found, side by side, the picture of the construction of a primitive door with a picture of the elbow joint which served as its model and inspirationthe perfect hinge.
WHAT CONSTITUTES A SPRAIN? NEW METHODS OF TREATMENT
According to the amount of correspondence received by me, there seems to have been a heated debate going on as to the nature of sprains. This is not surprising, for text books on surgery, themselves, are not entirely prepared to furnish a definition. “We talk about sprains, but who may define a sprain or explain its distinction from a contusion?” says one.
Good writers have said that a sprain is “an injury in which there is a sudden, momentary displacement of the bones entering into a joint, the parts returning immediately to their normal relations.” In other words, this means that a sprain is really a reduced dislocationa dislocation of the joint which has slipped back into place immediately, leaving only some torn ligaments.
However, most surgeons are prepared to admit that dislocation does not have to occur to produce a sprain. “A sprain is a joint wrenched due to a sudden twist or traction,” says a modem text book on surgery.
In any event, the essential part of a sprain is the strain, and possibly tearing of the ligaments around a joint.
The commonest joint in which this can occur is the ankle. In considering treatment of a sprained ankle, the most important thing is to be sure of the correctness of the diagnosis. There are many hundreds of people who have been crippled for life because they have allowed an injury of this kind to go on, saying to themselves, “Oh, it’s just a sprain.” What appears to be a sprain may conceal a broken bone or an unreduced dislocation. Therefore, a good x-ray picture is the first step in the treatment of a sprained ankle. Just because you can move the ankle or stand on the foot is no sign that it is not a broken bone or a dislocation.
Perhaps the greatest advance in the treatment of sprains came when an English surgeon found that in some young patients who had disobeyed him and gotten out and played tennis, the sprain recovered a week sooner than it did under the old treatment of absolute rest.
It used to be said that a sprain was worse than a fracture, but this was largely due to the old fashioned treatment which kept the patient in bed in a cast for several weeks, and frequently resulted in a stiff joint which took many months to restore to normal function. In general, nowadays, the sooner the patient gets around after the first few days, and uses the joint, the more rapid and complete the recovery. Some support must be given to the joint, and most surgeons do this by the use of adhesive plaster put around the joint in the form of a basket weave.