Muscle strain

“ It has been stated, that the excessive use of the muscles, as much as their inactivity, tends to weaken them. Nothing is more painful, than the keeping a muscle constantly on the stretch, without any relaxation [Pg 133] or change. This can be realized, by holding out an arm, perpendicularly to the body, for ten or fifteen minutes, if any one can so long bear the pain. Of course, confinement to one position, for a great length of time, tends to weaken the muscles thus strained. ”

“ A muscle used and released will keep normal, an unused muscle atrophies and and an overused muscle hypertrophies. There is a normal use and disease which must be maintained of a weak, dying flesh body results.
In the life of our modern civilization the ordinary individual does not use more than two-thirds of his muscular system, nor does he use one-third of his lung space. A few important muscles are made to do all the work, the rest lie dormant or, at the best, try to urge themselves upon the attention through lameness, weakness or stiffness. ”

“ If the injury be really to the nerves which control the muscles, as is generally the case, the matter is more difficult. The muscle swells, but this is primarily due to the overstrain of the nerves in the sudden effort they make to bear a crushing load on the muscle. The pain is from pressure in the swelling, and also from inflammatory action. ”

“ Infantile paralysis, which often appears suddenly, muscular atrophy, which develops slowly, progressive and chronic atrophy of the muscles, are also forms of muscular disease, combined with destruction of the accompanying nerve tissue.
A special group of muscular diseases consists of amyloid (fatty) degeneration of vital muscle substance, as for instance of the heart, the kidneys, the liver. These are also caused by faulty composition of the blood, which does not feed the muscles with the substances required and thus causes them to degenerate by developing too much fat. ”

“ Observe that but few of the muscles in the economy are found between two levers so great, consequently are capable of being so much distended, and especially of being so with a force greater than that of their contraction; for every muscular rupture supposes the excess of the external motion, which distends, over that of the fleshy fibres which contract to oppose this distension. If the external efforts were concentrated upon a single muscle, they would be able more often to overcome the resistance ”

“ It is curious that the majority of cases are males, and that it is transmitted by women who are not themselves its subjects. Many different clinical types have been described based upon the age of onset, the groups of muscles first affected, and the presence or absence of apparent hypertrophy; they are however all varieties of one affection, and in a case where there is an apparent enlargement of muscles there is really atrophy of the contractile muscle, fibres and overgrowth of fat and interstitial fibrous tissue; consequently this form of the disease is called pseudo-kypertrophic paralysis. ”

“ When the fibres of which a muscle is composed have become thus altered by fatty degeneration they become softer according, to the amount of it; they are more easily torn and may even tear across when the muscle is being used during life. The more a muscle is thus degenerated the weaker it is, because it contains less muscular substance and more fat. Not only do the heart and other voluntary muscles thus degenerate, but those of the arteries also. ”

“ Such employments call into action the muscles that support the spinal column in an erect position, and the languor or uneasiness is muscular pain. The long-continued tension of a muscle enfeebles its action, and eventually destroys its contractility. ”

“ The restriction of a healthy muscle causes it partially to lose its functioning ability, and habitual restraint and unnatural pressure brought to bear upon the muscles of the trunk result in local congestion and in displacement of special organs. Lungs, liver, and intestines, together with the organs of reproduction, suffer from the constrictive effects of the corset, and lack of nourishment, due to restricted circulation thus produced, causes atrophy of muscular tissue, since the latter is not adequately rebuilt. ”

“ The paralysis is usually symmetrical on both sides. Although the extensors are affected most, the flexors nearly always participate, and a careful investigation will show that they are weakened. If the paralysis continues, there is a wasting and degeneration of the muscle, but this is seen in paralysis from any cause. The muscular affection may cause deformities in the hands, shoulders, &c. Anæsthesia of portions of the skin is generally present in a greater or less degree. ”

“ The greater the displacement of the line of gravity, the greater the muscular effort required to maintain the equilibrium of the body. Up to a certain extent, exercising the muscle develops the strength and size of the muscle. On the other hand, when a muscle within the body is unused, it wastes; when used within certain limits, it grows. But when the corset splint is applied to the body of the young girl, it supplants the functions of the abdominal and back muscles, which is to hold the trunk erect, and these muscles gradually grow weak and waste. ”

“ We ought to look also to exercise for local effects; in order, in the first place, to keep the joints supple and counterbalance the tendency to incrustation of the cartilages, which is one of the consequences of age; and, in the second place, to keep the muscles as a whole in sufficient strength and volume. The muscle, as we have read, is "the furnace of vital combustion," and in developing the muscular tissue we favor the activity of combustion and the destruction of the refuse of nutrition. ”

“ He should make frequent attempts by stretching the rigid groups to overcome the spasm, which in large muscle-masses may be done by grasping with both hands, taking care not to pinch, and pulling the hands apart in the line of the muscle's long axis, thus stretching the muscles. Pressure will sometimes accomplish the same end, and it will be found in certain cases that by kneading during action,—that is, while the patient endeavors to produce voluntary contraction,—the result will be better. ”

“ When the nerve discharges its influence into the muscles, a very rapid molecular change takes place in the substance contained in the cartouches or muscular boxes, which contract, pressing their ends close together. Scarcely has the action of the nerves ceased than they relax and resume their previous form. It is well known, that when a muscle contracts, it becomes thicker and shorter; it suffices to take hold of the arm a little above the elbow and then to bend it in order to feel how the biceps muscle swells and hardens. ”

“ These cases are generally accompanied by round shoulders and flat chest, protrusion of the abdomen, and rotation of the vertebræ.
A muscle can be developed only by the active contraction and relaxation of its fibers. Continuous tension quickly tires and lowers its tone, so that exercises given for increasing muscular power should be comparatively quick and frequently repeated, while those that aim at the stretching of muscles and ligaments should be slow and long maintained. ”

“ Sometimes a muscle disappears entirely; usually the connective-tissue elements, including the interstitial cellular and adipose tissue, undergo proliferation, so as to mask the wasting of the muscles to some extent.
The morbid process in the nervous system is also a simple degenerative process. The nerve-fibres and cells atrophy first, and the connective-tissue proliferation which marks the sclerotic change of the diseased area is a secondary process. There is still considerable dispute among authorities as to which segment of the motor-conduits the degeneration begins in. ”

“ The site of rupture in individual muscles is remarkably constant, and is usually at the junction of the muscular and tendinous portions. When rupture takes place through the belly of a muscle, the ends retract, the amount of retraction depending on the length of the muscle, and the extent of its attachment to adjacent aponeurosis or bone. The biceps in the arm, and the sartorius in the thigh, furnish examples of muscles in which the separation between the ends may be considerable. ”

“ A muscle can only remain in a state of contraction for a few seconds, because the force of the muscular fibers is more or less exhausted during contraction. The more rapid the contractions, the sooner does fatigue manifest itself.
Like the steam engine, the muscles of the body, in performing their work, produce heat and motion. The fuel which supplies this force is taken into the body in the shape of food; it is prepared for use in the intestinal tract, and from there carried by the blood, to be stored up in the muscles and various tissues as latent force. ”

“ Exercising a muscle develops it up to its physiologic capacity, but if a muscle is habitually overworked, pathologic results occur, and instead of a quick, sharp contraction of the muscle, the contractions will be weak and uncertain, and, if carried too far, the muscle may eventually atrophy from overwork. ”

“ A contracted muscle, according to this view, is like a strong band of india-rubber pulling on two pieces of wood and drawing them together. In like manner, when a muscle contracts, a similar elastic power is developed that pulls upon the bones and causes movement. When the contraction ceases, the muscle returns to its original length, again by elasticity, but acting in the opposite way.
What is this property of irritability by virtue of which the muscle responds to a stimulus and contracts? ”

“ The muscle is well supplied with blood, and the nerve which endows it with energy is particularly well prevented from being compressed during the movements of the muscles amongst which it runs, any compression being very injurious. The upper edge of the blade-bone is notched, and a dense tissue or ligament stretches from one point of the notch to the opposite one, enclosing a small open space; now the nerve runs through this space, and is protected by the hard tissues of bone and ligament from the contraction of the soft muscles. ”

“ There is a disturbance of the normal smooth-running, indeed almost frictionless, mechanism by which muscles glide over one another. There are practically a series of joints in all muscular groups so as to permit just as free a play as possible of muscles over one another. Each muscle is covered with a glistening membrane so familiar {392} from our dissecting room days, which secretes a substance resembling a synovial fluid, to enable muscles to move upon each other without friction. ”

“ The actual structural change is the visible effect of the law that over-use of a muscle produces over-growth or hypertrophy. This is not a law of disease, but of purposeful utility, designed to meet emergencies of life. Still there is a further law in nature, that long-continued excessive use of any muscle leads to a form of hypertrophy28 which cannot maintain its vitality, but degenerates. Arteries must be treated as muscles, for their muscular coats contract and dilate, as circumstances demand, under the control of the nervous system. ”

“ The lengthened condition of the muscle is the natural condition, the condition of rest. The shortening or contraction is an effort which can only be continued for a certain time. The contraction bends the arm, and as long as the muscle remains shortened the arm keeps bent; but as the muscle lengthens, the weight of the hand and fore-arm, if there is nothing to prevent, straightens the arm out again.
It is in the muscle alone, in the belly made up of muscular fibres, that the shortening takes place. The tendons do not shorten at all. ”

“ When skeletal muscle is repeatedly stimulated by a long series of rapidly recurring electric shocks, its strong contractions gradually grow weaker until a fairly constant condition is reached. The record then has an even top—the muscle has reached the “fatigue level.” The effect of splanchnic stimulation was tried when the muscle had been fatigued to this stage. The effect which was often obtained by stimulating the left splanchnic nerves is shown in Fig. 11. In this instance the muscle while relaxed supported no weight, and while contracting lifted a weight of 125 grams. ”

“ When, because of exposure to drafts or the evaporation of moisture on the surface, there is a disturbance of the circulation in these intermuscular planes, the secretion which prevents the friction of muscle movements is disturbed. The blood is driven from the surface and some congestion and consequent heat accumulation occurs in the muscles, affecting particularly their contiguous layers. As a result, the muscle surfaces are no longer smooth and the muscles now have not as free play over one another as before. ”

“ A few experiments were performed on animals in which the nerve supplying the muscle was cut seven to fourteen days previous to the experiment. The muscle, therefore, had within it no living nerve fibres. The average normal threshold for the denervated muscle in 6 animals was 61.28 units. As in the normal muscle, the percentage increase due to fatigue was large. ”

“ The gap in the muscle becomes filled with blood, and this in time is replaced by connective tissue, which forms a bond of union between the ends. When the space is considerable the connecting medium consists of fibrous tissue, but when the ends are in contact it contains a number of newly formed muscle fibres. In the process of repair, one or both ends of the muscle or tendon may become fixed by adhesions to adjacent structures, and if the distal portion of a muscle is deprived of its nerve supply it may undergo degeneration and so have its function impaired. ”