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    The muscles: their construction, number, power and manner of action.-Muscles of the head and face, neck, back, chest, limbs, etc.-Pairs of muscles.-Muscles of the alimentary canal.-Disadvantageous action of muscles.-Rapidity of muscular motion.-Care of the muscles.-Muscular exercises.-Fascie

    Figure IV

    114. What are the muscles?HBH 43.1

    The moving organs of the body. Their grand peculiarity is their power of contraction, which is as wonderful as anything in nature. This is the element of all voluntary motion, and most, if not all, positively involuntary motion, in the living body. All the great motions of the body are caused by the movement of some of the bones which constitute the frame-work of the system; but these, independently of themselves, have not the power of motion, and only change their position through the action of other organs that are attached to them, which by contracting, draw the bones after them. In some of the slight movements, as the winking of the eye, no bones are displaced. The organs which perform this remarkable work are called Muscles. The red color of the muscles is owing to the presence of the numerous blood vessels which they contain.HBH 43.2

    115. Of what are the muscles composed?HBH 44.1

    They are composed of parallel fibers, of a deep red color, constituting lean flesh. Any person can examine a piece of boiled beef, or the leg of a fowl, and see the structure of the fibres and tendons of a muscle.HBH 44.2

    116. Of what shape is a muscular fiber?HBH 44.3

    It is long, round, and fine, like a thread. Any piece of lean meat can be easily divided in one direction into stringy fibers, which, by the use of appropriate instruments, can be subdivided till fibrils are reached, not so large as hairs, composed of a sheath enclosing minute particles, shaped like beads, placed end to end. Some might suppose lean meat had no regular shape, but the above proves that it has. The lean portions of our bodies are arranged in perfect order, as may be seen by observing Fig. IV, at the head of this chapter.HBH 44.4

    117. How are the fibrils that constitute muscles held together?HBH 44.5

    By a delicate web or sheath, which is perforated with minute tissues or cavities, and these become so compact together at the ends of the muscles as to form glistening fibers and cords, called tendons, or sinews, by which the muscles are attached to the periosteum, or surface of the bones. A few of the muscles resemble in structure a ribbon; others a cord; others are thin and expanded, so that they resemble a membrane. The muscles present various modifications in the arrangement of fibres, as relates to their tendinous structure.HBH 44.6

    118. How many muscles are there in the human body?HBH 44.7

    It is supposed that there are not less than four hundred and seventy distinct muscles of voluntary motion in the human body; about twice as many muscles as there are bones. They are nearly all arranged in pairs, each side of the body having the same kind. These are so arranged and adjusted, as to position and connection, that by the contractions of the different pairs, or individual muscles, all the voluntary motions of the lower limbs are performed. The function of respiration-which to a certain extent, is both voluntary and involuntary-also employs some of these muscles.HBH 45.1

    119. How much of the body is muscle?HBH 45.2

    The greater portion of the bulk of the body is composed of muscular tissue. It is the muscle that gives the body its plump appearance. These muscles not only serve as a means of moving the body, but, in the limbs, they invest and protect the bones, and some of the joints. In the trunk they are spread out to enclose cavities, and form a defensive wall, capable of yielding to external pressure and again returning to its original position.HBH 45.3

    120. How are muscles moved?HBH 45.4

    By contracting, or shortening. When a piece of India rubber has been stretched and you let go of it, it contracts. These cords have power to lengthen and shorten somewhat like rubber. Some muscles in contracting pull at one end, and some at both their ends.HBH 45.5

    121. How are all the actions and motions of the various organs of the body produced?HBH 45.6

    By the alternate contracting (shortening) and expansion (lengthening) of these muscular fibers. These muscles are so arranged as to act as antagonists to each other, some displacing a part, and some replacing it; and therefore they are termed the flexor and extensor muscles. The flexor muscles are considered to be generally more powerful than the extensor, and hence, when the WILL ceases to act, as in sound sleep and death, the body and limbs are partially fixed or bent.HBH 45.7

    122. Of what are the muscles composed?HBH 46.1

    Of bundles of fibers enclosed in a sheath; each fiber is composed of smaller bundles, and each bundle of single fibers called ultimate fibers. By a microscope it is seen that these ultimate fibers are composed of finer fibers called fibrils.HBH 46.2

    123. What is the appearance of the end of one of these fibers through a microscope?HBH 46.3

    It presents to us an appearance similar to that of the end of a compact bundle of very fine straws.HBH 46.4

    124. How many kinds of muscular fiber do anatomists distinguish?HBH 46.5

    Two: those of voluntary or animal life, those under control of the will; and those of involuntary or organic life, such as are used for breathing and digestion. Muscular fibers of animal life are composed of these bundles of fibrils, while the muscular fibers of organic life are flat, and are held together by fibers which are composed of a dense form of the same tissue. The muscles of animal life are developed on the external part of the body and are mostly attached to the bones, and they comprehend all of the muscles of the limbs and trunk, while the muscles of organic life are formed from the internal or mucous layer, and are situated in the hollow organs composing the respiratory, digestive and circulatory apparatuses.HBH 46.6


    125. When the muscular tissue is once destroyed, is it ever restored again?HBH 47.1

    Never; but when the muscles are wounded, with or without the loss of their substance, the breach is healed, and the parts united, by what is called areolar tissue, which is wholly insensible to the action of stimulants.HBH 47.2

    Figure V

    126. What does Fig. V illustrate?HBH 47.3

    This figure illustrates the muscles of the head and face. 1 is the muscle moving the eyelids; 2, muscle used in drawing the top of the head backward; 3, point of attachment of muscles 1 and 2; 4, muscles used in opening and closing the eye; 5, muscle that draws down the corner of the eyelid; 6, muscle used to expand the nostrils; 7, muscle surrounding the mouth, used in closing the lips; 8, muscle used to elevate the upper lip and expand the nose; 9, muscle used to elevate the upper lip; 10, 11, muscles that pull the angle of the mouth upward and outward, and are used in laughing; 12, the muscle which pulls the lower lip downward and outward; 13, muscle which pulls the angle of the mouth downward and outward, is used in making expressions of grief;HBH 47.4

    14, muscle that raises and protrudes the chin; 15, 16, 18, muscles used to move the jaw in chewing; 17, 19, 20, muscles which in lower animals move the ear; they have but little motion however in the human body; 20, the covering of a muscle; 22, 23, 24, muscles which, with their attachments to the neck, are used to move the lower jaw downward; 25, 26, muscles used in the movements of the head and shoulders.HBH 48.1

    127. How many groups of muscles are there in the head and face?HBH 48.2

    There are eight groups of muscles, namely: 1 for moving the eyebrows; 3 for moving the eyelids; 7 for moving the eyeballs; 3 for moving the nose; 7 for moving the lips; 3 for moving the chin; 5 to assist the lower jaw in the motions necessary in masticating food. One of these muscles passes over the temple, and is called temporal, from tempus, time, because here the hair begins to turn gray; 3 muscles of the ear. The muscles used for chewing food are attached to the lower jaw, near the joint; if their position was near the front part of the bone they would not contract sufficiently to bring the jaws together.HBH 48.3

    128. How many groups of muscles are there in the neck?HBH 48.4

    There are eight: The first has 2 muscles, used to bow the head forward; the second has 8 muscles, 4 depressors and 4 elevators. The depressors pull down the os hyoides, or bone of the tongue. The 4 elevators raise the os hyoides when the jaw is closed; the third has 5 muscles, and these aid the tongue in all its movements; the fourth has 5 muscles, which are used in swallowing food; the fifth has 3 muscles, used in all the motions of the palate; the sixth has 5 muscles, passing from the sides of the head down on to the breast, used to steady the head, and to lift the ribs as we draw the head backward in inhaling a long breath; the seventh consists of each of those muscles used in varying the tones of the human voice; the eighth has 8 muscles, those of the larynx-Adam’s apple; also used in producing articulate sounds. The muscles of the above eight groups, then, are those adapted to move the head and neck on the spinal column, to raise the shoulders, to control the motions of the mouth and throat, and to produce the sounds of the voice.HBH 48.5

    129. How many layers of external muscles are there in the back?HBH 49.1

    There are six layers, composed of at least thirty pairs of muscles. They give a firm attachment for muscles to move the extremities, and keep the trunk in an upright position. The first layer has 2 muscles and the second has 3, and these two layers give all the different motions to the shoulders; the third layer has 3, some of which are used in raising and depressing the back portion of the ribs in breathing, and some are used to give the spinal column its slight motion from side to side; the fourth layer has 7 muscles, holding the vertebral column erect, and assisting in steadying the head. When one of the muscles of this character act on one side alone they produce the rotation of the atlas on the axis; the fifth layer has 7 muscles. A portion of these contribute to the support of the back in an erect position. The others produce the rotary and other motions of the atlas on the axis; the sixth layer has 5 muscles. A portion of these raise the back part of the ribs in the inspiration of breath, the others help in supporting the body and holding the bones in position.HBH 49.2

    130. How many classes of muscles belong to the thorax or chest?HBH 50.1

    There are three classes of muscles belonging to the chest, and these belong also to the upper extremities. The first class is 11 internal muscles; the second class is 11 external muscles. These muscular, cordy fibers fill the spaces between the ribs outside and within the front of the chest, and they cross each other; the third class is situated within the chest, and connects the breast bone with the ends of this first and second class of muscles, and also connects them with the cartilages of the second, third, fourth, fifth, and sixth, ribs. The lower fibers of this muscle connect also with the internal muscles of the abdomen. These three classes of muscles raise and depress the ribs and draw down the cartilages of the ribs, and thus assist in breathing.HBH 50.2

    131. How many muscles regulate the movements of the abdomen?HBH 50.3

    Nine, and the ninth of these is called the diaphragm. It is a partition across the body just below the lungs, with an opening near the center. It separates the thorax from the abdomen. Its point of attachment to the body is just below the ribs. When the diaphragm is relaxed, it presents the appearance of an inverted and irregularly-shaped cup. When in a state of contraction its surface is nearly a plane. This muscle enlarges the chest by depressing its lower surface, as in the case of holding a full breath in the lungs. The nine muscles of the abdomen assist in drawing down the ribs, in drawing in the small of theHBH 50.4


    back, or in turning the abdomen sidewise. They also diminish by their action the size of the abdomen, and thus assist in breathing.HBH 51.1

    Figure VI

    132. What does Fig. VI represent?HBH 51.2

    In Fig. VI are seen the front muscles of the trunk. 1, 2, 3, are muscles used in moving the shoulder; 4, a muscle raising the ribs by the movement of the shoulder. It is this muscle which draws the shoulder forward in a case of diseased lungs; 5, 6, muscles used in raising the shoulder, or in producing its rotary movements; 7, 8, 9, muscles used in movements of the arm and shoulder; 10, 11, muscles moving the ribs in breathing; 12, 13, 16, 18, muscles moving the abdomen, and to bend the body forward. They are used in laughing, crying, singing, and shouting; 14, the principal muscle for throwing the leg forward, called Poupart’s ligament. The other numbers indicate the muscles supporting the abdomen, and assisting in the motions of the hip joint.HBH 51.3

    133. How many muscles are there connected with the outlets of the bowels?HBH 52.1

    There are 8, all acting their part in carrying waste matter from the system.HBH 52.2

    134. How many muscles are required for the movements of the arms and fingers?HBH 52.3

    There are about 46 muscles to each arm. And in order that the fingers may be slender, and easily moved, the muscle that moves them is placed in the fore arm, and the tendons for the movement of the hands and fingers are made as slender as possible. Some of these extend only to the wrist to bend it upon the arm. Some of them pass to the very finger ends, passing under a ligament like a bracelet, at the wrist.HBH 52.4

    135. How many muscles are there in each leg and foot?HBH 52.5

    About 52 in each leg and foot, and these are used to make all the different motions of the leg and foot. Some of them are attached to a small ligament at the knee, called the patella-knee-pan-which serves the purpose of a fulcrum over which the cord pulls in moving the lower limb and foot. These muscles are all advantageously disposed of for power, and are so arranged as to hold the limbHBH 52.6


    erect, and to balance the body upon the upper portion of the limb.HBH 53.1

    136. How much is it supposed that a muscle contracts, and what is the process of the contraction of a muscular fibril?HBH 53.2

    It is supposed that muscles are capable of contracting about one third their length. This contraction or shortening of the fiber is owing to a change in the diameter of the component parts of an ultimate fibril. This action may be well illustrated by placing a dry rope in water: wetting it increases its diameter but shortens its length.HBH 53.3

    Figure VII

    In Fig. VII the contraction of a muscle is illustrated. In a, the beaded portions of the fibrils are at rest. The diameters of those portions are greatest lengthwise of the fibrils. In b, the muscle is contracted, and the beaded portions have their longest diameters crosswise of the fibrils. The natural state of a muscle is what is called its tonicity, and it is supposed to be a constant strain or stretch. This keeps the muscle in a position in which it is always ready for action. Just what the element is that causes the motion of muscle is not yet decided. It is certain however that a good supply of oxygen and electricity in the blood greatly facilitates the action of the muscle, and so muscular exertion can be continued for a much longer time in the open air than otherwise.HBH 53.4

    137. Which is the largest tendon in the body?HBH 54.1

    It is the one which is attached to the calf of the leg, extending down to the heel, and which is used to raise the body upon the toes. It is called the tendon of Achilles, because the great Grecian warrior Achilles is said to have been killed by the wound of an arrow in this tendon.HBH 54.2

    138. What is found connected with the muscles?HBH 54.3

    Around the fibrilla of the muscle, but not entering into them, is woven a very beautiful net-work of very fine capillaries, communicating with arteries on the one hand and veins on the other, so that a plentiful supply of blood is constantly poured around the contractile elements of the muscle. Thus its exhausted energies are replenished, and its substance nourished. The veins receive the unappropriated blood, and conduct it back to the heart; and thus a continual stream of fresh arterial blood is poured through all the muscular tissue. By this means the vitality of the muscle is maintained. The involuntary muscles are even more abundantly supplied with vessels than those of animal life.HBH 54.4

    139. What other peculiarities are there in the arrangement and action of muscles?HBH 54.5

    Each muscle is provided with one or more antagonistic muscles, or those that produce motion in an opposite direction. The only exception is in a few muscles of the head and neck. When one set of these muscles are contracted, the others must relax, otherwise the body would not move. Medicines that produce nausea, or sickness at the stomach, will relax all of these muscles. Another peculiarity is, that all the component parts of a muscle do not contract at once, but one portion of the fibrils contract, then another, and another, and so on. If the whole muscle contracted at once, its action must necessarily be very short. While the muscle is contracted decomposition is going on, and the blood is shut out of that portion of the muscle; but as different parts of the fibrils take up the process of contraction, there is a partial building up of the muscular structure from the nutriment of the blood, even while contraction of the other parts is taking place.HBH 54.6

    140. What is the arrangement of the muscles of the alimentary canal?HBH 55.1

    As it is necessary in the performance of the general functions of the alimentary cavity, that there should be motion, as well as innervation and secretion, muscular fibers are everywhere attached to the back of the mucous membrane forming that cavity. The general arrangement of these fibers consists of two layers: the first composed of circular fibers, which surround the meat pipe, the stomach, and the small and large intestines, like rings, or sections of rings; the second layer is composed of fibers running lengthwise of the meat pipe, stomach, and intestinal tube. By the contraction of the circular fibers, the size of the cavity is diminished. By the contraction of the longitudinal fibers the parts are shortened. By their combined action they give the parts an undulating motion. This muscular coat is stronger and thicker, in the meat-pipe and stomach, than in the small intestine, and stronger in the small than in the large intestine. In the rectum, or outward terminus of the intestines, the muscular coat becomes thicker and stronger. In the pharynx the muscular coat is composed of six constrictorHBH 55.2


    muscles, the fibers of which form sheets which cross each other in various directions. By the action of these muscles, both the length and caliber of the pharynx are diminished. In the stomach the fibers are arranged in three different directions: longitudinally, circularly, and obliquely.HBH 56.1

    The muscular coat of the alimentary organs, and particularly of the stomach and small intestine, is more or less developed in power and activity, according to the character and condition of the food on which the person habitually subsists. That food calling for a proper amount of muscular action in the stomach and intestines increases their strength, while food of an opposite kind conduces to emaciation, and inactivity of those fibers, rendering the action of the stomach and bowels sluggish and feeble.HBH 56.2

    Figure VIII

    141. Do the muscles act at the greatest advantage, or are they so arranged that power is sacrificed to save time?HBH 56.3

    The attachment of muscles for the movement of the body is at a great disadvantage, as will be seen by looking at Fig. VIII. The lines, a, b, c, are designed to represent the arm; a, the shoulder; b, the elbow; c, the hand; d, the point of attachment of the muscles which are to move the fore arm and hand. If the muscle was attached from a to c, more weight could be lifted than with an attachment from a to d; but it would take more time to lift it as the muscle would have to contract more. And with the present contractile power of a muscle it would not contract sufficiently to raise the hand to the head. The muscles are usually attached near the joints, and as a hand near the hinge of a gate must use great exertion to move it; and as the hand near the hinge moves but little and slowly to move the farther end of the gate rapidly, so with the action of muscles, as illustrated above, they are arranged with reference to saving time, but it is an expenditure of force. All muscular action, as we have shown, is attended with a great waste of muscular fibril, so no more muscular exercise should be put forth than is necessary for health and to accomplish our necessary work. For this reason farmers, mechanics, and all laboring classes, should have their tools handy, and calculate their work to save all unnecessary steps and blows; let the “head save the heel.” Houses should be arranged so that the woman’s work will be handy, and all useless steps avoided. It will save the health of women who otherwise would be overworked. A person raising a hundred-pound weight in the hand, exerts a force on the muscle equal to eighteen hundred pounds. The act of leaning over and straightening up is a strain on the muscles of the legs of many thousand pounds. The muscles of some lower animals are much stronger in proportion to their size than those of man. A flea harnessed, will draw seventy or eighty times its own weight, while a horse draws but six times its own weight. The common beetle bug has been known to throw a weight placed upon it three hundred and twenty times heavier than itself.HBH 56.4

    142. What examples illustrate the rapidity of muscular movement?HBH 57.1

    Some persons have pronounced as many as 1500 letters in a minute, combined of course in words; but to do that, it would require the contraction and relaxation of one or more muscles to each letter, each contraction occupying not more than one-fiftieth of a second. The wings of some animals must move many thousand times in a minute to produce the humming which is heard while their wings are in motion. Some birds fly 60 feet in a second, while a race horse scarcely exceeds 40 feet in the same time. A falcon of King Henry II, flew from Fontainebleau to Malta in one day, a distance of about one thousand miles. The precision of muscular movement is seen in the rapidity with which a singer can accurately strike notes in any part of the scale. These sounds are all produced by contracting and relaxing the muscles of the larynx.HBH 57.2

    143. How may the muscles be strengthened, and kept in a healthy condition?HBH 58.1

    The muscles, to be kept healthy, should be used. Using the muscles increases the flow of the blood through them, and thus the waste, or decomposed particles, are carried off, and nutritive particles are placed in their stead. Plenty of exercise in the open air is imperatively necessary for a healthy condition of body in students, professional men, in-door mechanics, and females. Farmers who work in the open air, if not overworked, enjoy the benefits of the wholesome air of heaven. This exercise should be in a condition free from care, or burdening of the brain, thus giving the blood a chance to flow healthfully through all the system. These exercises in the open air are better, because then the oxygen is freely inhaled into the system, and thus through the blood the muscular system is built up. The air contains more oxygen in cold than in warm weather, and therefore greater muscular activity can be attained in winter than in summer, and for this reason, other conditions being equal, the body will gain in weight faster in winter than in summer.HBH 58.2

    144. What else is necessary in relation to muscular exercise?HBH 59.1

    Muscular exercise, or labor, is more conducive to health, and more of it can be endured, if it is done gradually, than if a violent exertion is made. After work we need repose. After the muscles have been used violently, or after vigorous exercise, the muscles should gradually be brought into a state of rest. Sleep is the grand restorative after severe muscular exertion; this alone gives back to the muscle its life and strength.HBH 59.2

    145. Mention some of the most healthful exercises?HBH 59.3

    Riding on horse-back, walking, climbing mountains, running up and down stairs, sawing wood, planing boards, rotary motions with both arms extended while the lungs are filled with air, or carefully moving the arms back till the backs of the hands touch if possible.HBH 59.4

    146. What should be the position of the body in standing or walking in order to properly develop the muscles?HBH 59.5

    The body should be upright; with the head, shoulders and hips thrown back, and the breast forward. Constant bending over will cause a round-shouldered, crooked, mean, diminutive appearance. But the appearance is the smallest evil. It causes the bones of the chest to press upon the internal organs of the body, and hinders their healthy action, causes short breathing, and pain in the chest, weakness of the lungs, and finally consumption. A person who stands erect, can stand with more ease, labor better, and travel farther in a day, than one who stoops. Students, when sitting at their studies, or in writing, should avoid a stooping posture. If we always keep the body in a proper position it will tend to make the back bone firm and strong. In all bodily or mechanical labor the body should be bent, or lean on the hip joints; the trunk should be kept as straight as possible.HBH 59.6

    147. What can we say, in conclusion, of the muscular system?HBH 60.1

    The muscles of the human system are a wonderful combination of flexible cords, by which, in an instant, the body, or any part of it, may be moved by the will in almost any conceivable direction.HBH 60.2

    148. What protecting coat invests these soft structures, and the delicate organs of the body?HBH 60.3

    They are everywhere invested by bandages, called fascie. They are composed of fibrous tissue of various thickness, and are divided into two classes, called cellulo-fibrous, and aponeurotic.HBH 60.4

    149. What of the cellulo-fibrous fascie?HBH 60.5

    It invests the whole body between the skin and deeper parts, and affords a medium of connection between them. It is composed of fibrous tissue, arranged in a cellular form. It affords a yielding and elastic structure, through which the minute vessels and nerves pass to the papillary layer of the skin, without obstruction, or injury from pressure.HBH 60.6

    150. What of the aponeurotic fascie?HBH 60.7

    It is strong and inelastic, composed of parallel tendinous fibers, connected by other fibers passing in different directions. In the limbs it forms distinct sheaths, inclosing all the muscles and tendons constituting the deep fascia. In the palm of the hand and sole of the foot it is a powerful protection to the structures.HBH 60.8

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