Muscle

“ This diagram will give you a conception of what we mean by a muscle. It shows the muscles of a frog's leg. You observe that, as a rule, a muscle springs from a bone, and is attached at the other end to another bone, a joint, sometimes two or more joints, intervening. One end of such a muscle as the gastrocnemius (Fig. 6) muscle terminates in what is called a tendon or sinew—a fibrous structure which is attached to a membrane covering the bone. The muscles are the living ropes that pull the parts of the animal machine. ”

“ The redness of a muscle, in fact, depends in a great measure on the degree of exertion it undergoes; thus when a limb becomes motionless from palsy, the muscles uniformly become pale.—The function of a muscle consists in its contracting or shortening itself, in consequence of the application of certain stimuli or excitements; the effect of this contraction is, that the different bones to which the muscles are attached are moved in various directions. ”

“ From these facts, as well as from the great force with which the muscle contracts, one must conclude that the muscle is a transformer of energy—that within its protoplasm, chemical changes take place whereby the potential energy of oxygen and food is converted into the kinetic energy of motion.
Fig. 113—Capillaries of muscles. Plan of Using Muscular Force.—Two difficulties have to be overcome in the using of muscular force in the body. The first of these is due to the fact that the muscles exert their force only when they contract. They can pull but not push. ”

“ The muscle is not found in the pig or in the carnivora.
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Muscles of the Arm
We should remember, at the outset, that in man the muscles of the arm are divided into two groups: one anterior, which contains the biceps, brachialis anticus, and the coraco-brachialis; the other, posterior, which is constituted by a single muscle, the triceps.
In animals, we find them in the same number and arranged in analogous fashion—that is to say, in two groups—with respect to the bone of the arm. ”

“ Why does the muscle contract when that something reaches it? We must be content to say that it is the property of the muscle. But it does not always possess this property. Suppose you were to tie a cord very tightly around the top of the arm close to the shoulder. If you tied it tight enough the arm would become pale, and would very soon begin to grow cold. ”

“ The muscle, directly that “something” comes to it along its nerves, contracts, shortens, and grows thick; it rises up in the arm; its lower tendon pulls at the radius; the radius with the ulna moves on the fulcrum of the humerus at the elbow-joint, and the arm is bent. ”

“ Muscle.—Muscle is the contractile tissue of the body, that tissue by which the various parts of the body are moved. Thus it forms the main bulk of the limbs, back, neck and body wall. Most of the viscera too possess well-developed muscular coats. When separated into its constituent parts it is seen that muscle in all instances is built up of a number of long fibres. These are of three well-defined types. Those forming the skeletal muscles are of large size, even in some instances up to 12 cms. ”

“ Pronator Quadratus.—This muscle conforms to the general law which we have already pointed out in connection with those which have for their action the rotation of the radius around the ulna. We remember, indeed, that when the bones of the forearm are fused with one another, the muscles which are destined to produce a mobility which has then become impossible disappear at the same blow. ”

“ Can he predict, with all his learning, that if a certain muscle is drawn up in a particular manner, it will present a particular appearance in a different part of the arm or leg, or bring out other muscles, which were before hid, with certain modifications? ”

“ These are made up of different kinds of muscle cells and act in different ways to cause motion. The [pg 244] striated muscular tissue far exceeds the others in amount and forms all those muscles that can be felt from the surface of the body. The non-striated muscle is found in the walls of the food canal, blood vessels, air passages, and other tubes of the body; while the muscular tissue of the heart is confined entirely to that organ. ”

“ Strip a strong arm, and regard the knotted muscles when the hand is clenched and the arm bent. Is this exhibition of energy the work of the muscle alone? By no means. The muscle is the channel of an influence, without which it would be as powerless as a lump of plastic dough. ”

“ And in many cases several muscles look like one single muscle in the increase of fat; and in many cases, in growing lean or old, one single muscle divides into several muscles. And in this treatise, each in its place, all their peculiarities will be explained—and particularly as to the spaces between the joints of each limb &c. ”

“ Making the Muscles Strong.—No persons use all of the five hundred muscles in the body every day. In slow walking only about twenty muscles are used, while in running more than four times that number are called into action. Muscles which are not used get lazy and weak.
Every time a muscle is made to act the blood vessels enlarge and bring to it more blood to supply food. The more food the muscle has the stronger it grows. The right arm is used more than the left in most persons. ”

“ Every muscle, in fact, consists in the first place of a mass of muscular substance. This muscular substance is made up of an immense number of soft strings or fibres, all running in one direction and done up into large and small bundles. At either end of the muscle these soft muscular fibres are joined on to firmer but thinner fibres of connective or fibrous{29} tissue. And these thinner but firmer fibres make up the cord or band of tendon with which the muscle finishes off at either end. ”

“ For example, the strongest muscle in the body is that by which one rises on the toes. This muscle operates by pulling upward at the back of the heel. If it were located right at the ankle, where it would have to be if attached directly to the place where its force is exerted, the resulting clumsiness can easily be imagined. ”

“ In studying the action of a muscle it is necessary to note its points of attachment to harder structures, either bone or cartilage. Nearly always one such point is more fixed than the other, and from this the muscle pulls when it contracts. ”

“ How the Muscles Act. The commonest form of muscle that we see is the red, lean meat of beef, mutton, or pork; and this will give us a good idea of how our own muscles look. All muscles, whatever their size or shape, are made up of little spindle-shaped or strap-shaped cells, or wriggling "body-cells" arranged in bands or strings. The size of a given muscle depends upon the number of cells that it contains. ”

“ The term muscle signifies every organ of the human body which, by contraction, produces the movements of the organism. Muscles are of the greatest variety and strength, but all consist of the same chemical elements, and can be regenerated in case of disease, like every other organ, by feeding the patient with the chemical substances which the muscle cells require. ”

“ A microscopic examination of the muscle shows that it is composed of minute fibres, each of which on contraction swells up into a spindle shape. A mass of such fibres aggregated together constitutes a muscle, and every muscle is attached at either extremity, by means of a tendon, to a bone. Both extremities of a muscle are never attached to the same bone—otherwise the muscle would be absolutely useless. Usually there is only a single bone between the two ends of a muscle, but in exceptional cases there may be more. ”

“ It is also most important to see that the exercise for each muscle shall be that for which the muscle is naturally adapted; and exercises designed to bring the muscles of the fingers or wrists into their utmost state of efficiency will be evidently utterly different from those by which we cultivate the muscles of the loins, the back, or the chest. ”

“ This interpretation seems, indeed, to be directly at variance with the fact that muscle does not diminish in bulk during contraction but merely changes its shape. That which we see take place with the muscle as a whole, is said also to take place with each fibre—while it shortens it also broadens. ”

“ Full contraction of a muscle is absolutely necessary to produce the best results; i. e., the greatest possible shortening of which a muscle is susceptible. To illustrate. If a twelve-inch muscle is contracted to the full—say seven inches—then fresh blood, necessary to its nutrition is caused to flow through all its smallest vessels ”

“ Structure of Voluntary Muscles. The main substance which clothes the bony framework of the body, and which forms about two-fifths of its weight, is the voluntary muscular tissue. These muscles do not cover and surround the bones in continuous sheets, but consist of separate bundles of flesh, varying in size and length, many of which are capable of independent movement.
Each muscle has its own set of blood-vessels, lymphatics, and nerves. It is the blood that gives the red color to the flesh. ”

“ Moreover, we know that all the movements of the limbs depend on the muscles, and that these muscles are opposed to one another in such a manner, that when one of them shortens, it draws along the part of the body to which it is attached, and so gives rise to a simultaneous elongation of the muscle which is opposed to it. ”

“ In contracting, the muscles become the seat of many small transverse wrinkles, sensible especially in the contractions of oscillation, less apparent in those of the whole of the muscle, and almost nothing, when a muscle being laid bare in a living animal, contracts with a small degree of force. ”

“ To a gradually increasing extent, the contracting force, instead of being withdrawn when the muscle is inactive, remains; and, as we have already seen, an arm or leg that should be passive is lifted, and the muscles are found to be contracted as if for severe action. ”

“ The painter who is familiar with the nature of the sinews, muscles, and tendons, will know very well, in giving movement to a limb, how many and which sinews cause it; and which muscle, by swelling, causes the contraction of that sinew; and which sinews, expanded into the thinnest cartilage, surround and support the said muscle. ”

“ It is evident from the foregoing observations that a great number of things concur in the contraction of the muscles, and that one should be thoroughly acquainted with that wonderful machine, our body, and the elements with which we are surrounded, to describe exactly one single muscle and explain its action. ”

“ Then the immense power of muscle is displayed in the concentrated energy of the spring; he flies through the air and settles on the throat, usually throwing his own body over the animal, while his teeth and claws are fixed on the neck ”

“ We may class muscles as striated or voluntary and unstriated or involuntary. A third class, mixed, is represented by the heart muscle. The striated is represented by the skeletal muscles, and the unstriated by the thin muscular layers that form part of the wall of the stomach, intestines, bladder and other hollow organs. ”

“ The muscles are the chief organs of motion, and consist of collections of fine fibres or strings, united in [Pg 75] casings of membrane or thin skin. They possess an elastic power, like India rubber, which enables them to extend and contract. The red meat in animals consists of muscles. Every muscle has connected with it nerves, veins, and arteries; and those designed to move the bones, are fastened to them by tendons at their extremities. ”

“ The contraction of a muscle, besides compressing its components, compresses neighbouring tissues; and every instant contractions and relaxations of muscles go on throughout the limbs and body during active exertion. ”

“ The muscles at f, are those which enable us to turn the hand and arm outward. Every different motion of the arm has one muscle to produce it, and another to restore the limb to its natural position. Those muscles which bend the body are called flexors ”

“ The unstriped muscle is very simple, consisting merely of long spindle-shaped cells, but the striped or voluntary muscle is of more complex construction. Every voluntary muscle consists of myriads of tiny fibres, bound together in little bundles, enveloped in a kind of sheath. Fig. 24 is an example of this muscular fibre, taken from beef. When soaked in spirit, it often splits into a number of discs, the edges of which are marked by the transverse lines. ”

“ The elements that enter into the composition of the solid matter are as follows:
The general composition of a human muscle is shown by the following table: [234]
The muscles of the flesh form a large proportion of the weight of the whole body. Calculated for a man of 150 pounds’ weight:
The property of muscular tissue by which its peculiar functions are exercised, is its contractility—contraction or shortening. ”

“ The muscles are compressed into tendinous cords at their ends, by which they are united to the bones.
They are arranged in pairs, having reciprocal actions—each muscle having a companion muscle by which the part which it moves is restored to its original position, when the influence of the first muscle is withdrawn, and the stimulus given to bring back the part.
943. Why can we raise our fingers?
Because muscles which lie on the fore-arm, and have their [Pg 225] tendons fastened at the ends of the fingers, contract, and by becoming shorter, draw the fingers upward, and towards the arm. ”