Popular Science Monthly/Volume 20/March 1882/Muscular Expression of Nervous Conditions

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COARSE or extensive paralyses, such as involve one or both sides of the body, and other profound disturbances of the muscular system, have received much attention from clinical and pathological observers, and by the accumulation of their joint observations much knowledge has been gained as to the symptoms that result from lesions of the brain. This should encourage us to observe in all cases the conditions of the muscles, knowing that the movements correspond to certain states of the moto-centers, and looking upon such nerve-conditions as indications or expressions of the states of those centers. All expression of feeling is effected by muscular action, whether it be by words, by facial movement or gesture, movements effected by voluntary muscles; or expression may be produced by dilatation of the pupil, erection of the hair, or disturbed action of the heart, these being due to the conditions of inorganic muscular fibers. I have been accustomed to regard the nerve-muscular condition of "nervous cases," when seeking definite signs by which to describe them, in the light of the principle that movements depend upon nerve-muscular stimuli originating in nerve-centers. Examples may easily be given, showing how we commonly judge of the state of the nervous system by muscular conditions. Note the stooping attitude and spiritless gait of a tired man as compared with that of the same individual when rested and refreshed. Incipient intoxication is indicated by a reeling gait, unsteady hand, and muscular tremor. Expression may be indicated by the position of the head, which is seen firmly upright in defiance, drooping in shame; is commonly held on one side in nervous women and girls convalescent from chorea, the first example cited of an asymmetrical gesture. The artist's brush or pencil, the sculptor's modeling-tool and chisel, the pianist's and violinist's finger-touch, indicate the training and actual condition of the working of his brain. The educated and refined singer trains and refines his whole mind, i. e., his brain, and is well aware that his "whole soul," as he may express it, comes out in the action of the muscles concerned in producing his song and musical notes. In the infant the condition of the nervous system is best recorded in terms of nerve-muscular phenomena. It laughs, and is playful; reflex action is well marked when a finger is placed in the child's mouth. The eyes are moved and directed toward any object looked at; these are conditions of healthy action. It is well known that in the convulsive state the fists are often closed, with the thumbs turned in. All these examples of expression are nerve-muscular conditions; the movement, the attitude, the gait, result from states of the brain or spinal cord.

The normal movements of the eye are seen in the varying conditions of the pupil under the influence of light, in the changes accompanying accommodation for near and distant vision, and in the turning of the eyes in any given direction, a movement in which the parallelism of the axes of the organs is usually maintained. Each of these movements is supposed to be governed by a particular brain-center; and the convergence of the lines of the axis which takes place when the eyes are called upon to look at some very near object involves a complicated association of muscular conditions. The associated movements of the eyes may be completely lost in deep anæsthesia from chloroform, in coma from alcoholism, or in the profound sleep of infants. If, in an adult deeply under the influence of chloroform, the eyelids be gently raised, the pupils will be seen minutely contracted, often to a pin-point, the eyes having at the same time lost the parallelism of their axes. One eye may move upward or outward, while the other remains quiet, or moves in a different direction or at a different pace, thus causing a temporary and varying strabismus. Usually these movements are confined to the horizontal plane; less commonly the eyes assume a different level, one being in the horizontal plane while the other is turned downward. In these cases the coordination of the movements is restored with returning consciousness.

Loss of associated movements may sometimes be easily detected in very weakly infants while awake and sucking at the bottle, and in cases of meningitis and other conditions of coarse brain-disease; and sometimes appears to be chronic in paralyzed or partly paralyzed and idiotic persons. Many of the lower animals have the power of moving either eye separately and independently, a fact which leads to the suggestion that the brain-center that co-ordinates the movements of the two eyes may be looked upon as one more recently developed in the ascent of man.

In nystagmus, a disease in which the eyeballs oscillate rapidly, usually in an horizontal, rarely in a vertical direction, the parallelism of the axes is generally maintained. In one recorded case, the eyes were capable of being turned slightly to the right, not at all to the left; yet, when an object on which the eyes were fixed at a distance was gradually brought close to the face, the eyes converged upon it, the right eye moving about fifteen degrees to the left to bring the line of its axis upon the object. Such an affection may be accounted for on Ferrier's theory by supposing that one of the brain-centers controlling the horizontal movements of the eyes had been destroyed. Most of the ordinary movements of the eyes in health are probably horizontal, and are least voluntary; and because they are very simple, and do not involve movements of the muscles of the eye, they are regarded as the least intellectual. The vertical movements are more complex, calling special muscles into play, and may, therefore, be considered more intellectual. From direct observation, it appears to me that intellectuality is represented by the movements of the eyeballs in their orbits. When an individual in looking at an object moves the eyes by the action of the recti muscles so as to direct them towards it, the movement is more intellectual than when the head is turned so as to direct the eyes in the required direction. A bright, healthy, well-developed infant turns its eyes well in the orbits in looking about; not so a dull, wasted child. Again, intellectual people usually move the eyes in their orbits in looking at any object; the low and vulgar often move the head in the direction required. The movements of the face, like the other forms of expression by muscular action, are generally symmetrical. Asymmetry is, however, seen in facial palsy, in sneering, and occasionally in the one-sided grimaces of very nervous people. Certain commonly marked lines in the face—horizontal and vertical lines in the frontal zone, the naso-labial grooves, the lines of the upper and lower lips, and the positions of the angles of the mouth—exist as the result of the puckerings produced by muscular action. Among the facial muscles, intellectuality appears to be most commonly expressed in the frontal and middle zones, and by the action of the corrugator and orbicularis-oculi muscles. It has been possible among out-patients to accept the facial appearance as a physical sign of mental as well as of physical and organic suffering. In cases where the muscular expression has been marked, some painful condition and some source of anxiety or mental distress has almost invariably been found. A person suffering from headache, or who "looks as if he had a headache," presents an appearance of depression, heaviness, fullness about the eyes, especially about the under eyelid; the orbicular muscle and adjacent parts are flabby, with the skin hanging loosely. If the patient can be induced to laugh, the muscle recovers its tone, the skin is tucked well in against the eyeball, and the appearance of depression or expression of headache is lost for a time. The life of the eyes is given, not by the eyeball, which is almost wholly lacking in expression, but by the conditions of the eyelids and of the muscles that move them, and in some degree by the muscles which move the eyeballs. The action of the muscles about the angles of the mouth is affected by a very moderate amount of brain disturbance. The value of the study of the nerve-muscular conditions of the face is finely illustrated in the case of the passive, expressionless face which may be woke up, "lighted up," made to express the whole soul in the face simply by conditions of the tension of the facial muscles resulting from the mental state. Thus, often, great and pleasing beauty is seen in faces unattractive when at rest. Conversely, some faces are beautiful in their passive condition, but lack expression and interest when in action from mental work; women having such faces talk but little. Surely from these two conditions it is suggested that the passive form and color of a face are qualities not so great, not so mind-indicating, as the mobile expressions produced by muscular tension.

Probably the most expressive of the muscles of the upper extremity are those that move the fingers, or which produce the "finer movements," motions in small arcs, as distinguished from the "coarser movements," or those that are made from the shoulder or the elbow. It is, of course, in the free or disengaged hand that we must look for examples illustrating the condition of the brain which governs it. If the muscles be employed in some definite act, such as holding an object, or in an act of manipulation, such as sewing, then the movements are directed to accomplish the aim attempted, and are not simply indicative of the condition of the brain, as may be the case with the free hand when unconsciously expressing the mental condition by gesticulation. When, on the contrary, the hands are left free and disengaged, as the hand of the orator, which unconsciously expresses by its position or movement the general mental state of the speaker, we have in this muscular movement an expression of the man's mind. It is as unreasonable to look for the state of the mind to be expressed in the position and action of the hand engaged in definite, voluntary, purposive acts, as to look in the face when the sun is shining full in the eyes, or the lips are engaged in eating, or other movements affecting the regularity of the breathing. Still it is true that in either case the manner of performing the act may be indicative of the mental state, but the muscles of the face or hand are not engaged in expressing the mental state.

In art of the present day we but seldom see the hands represented as disengaged; usually they are painted or sculptured holding some object, or resting on some part of the figure; such are hands engaged or resting from labor, or performing some act of toil, not engaged in expressing some action of the mind.

When a very nervous child, or one convalescent from chorea, holds out its hands in front on a level with the shoulder, and with its fingers spread out, we commonly see the nervous hand. As the palms are turned down, the wrist droops slightly. The metacarpo-phalangeal joints are moderately extended, the first and second internodes being either flexed or kept straight. The thumb is simply extended backward, and somewhat abducted from the fingers; and a twitching of the fingers is frequently observed.

The energetic or powerful hand is the reverse of this, and is probably seen in life only under certain conditions of the mind, producing what we call "mental states," or states giving energy and the feeling of strength.

The most natural position of the hand is that of rest, and here analysis shows all the joints in flexion. The hand may be seen in perfect rest during sleep, or when the man is resting, engaged in quiet, unexciting conversation.

The antithesis of this is a hand in general extension or ortho-extension. The term ortho-extension is used to imply that the joint is so far extended as to place both the bones constituting the joint in the same straight line. If extension be full or complete, the bones form an obtuse angle with each other.

In the "ortho-extended hand," the axes of the metacarpal bones (hand-bones) and of the digits are in the same plane with the bones of the fore-arm, and the position is represented in which a strong man naturally holds out his hand when requested to put it forward. A healthy child, when it runs in its play or to meet a friend, commonly holds out its arms, the hands assuming the "energetic position"; and this, as the result of observation, is, I think, characteristic of a healthy, nerve-muscular condition; healthful children in pictures by the best masters are often thus represented. When a child is in a state of convulsion it is well known that usually the hand is closed, with the thumb turned in upon the palm, the fingers being flexed around it. Such a position of the band in a child when ill is very indicative of a state of the nervous system predisposed to convulsions.

Equally characteristic with the passive positions of the hands are the muscular movements of the fingers—twitching, tremors, and rhythmical movements. These conditions have been more fully studied and described than the characteristic passive positions (postures), and they have long been considered as visible muscular conditions expressive of the states of the nerve-centers. The varieties of finger-twitching may be described as—1. Flexor-extensor, the primary movement being that of flexion, followed by a secondary extension movement. This may be seen in a variety of cases, and in particular is seen in what is called "picking the bedclothes" in the typhoid state preceding fully developed coma. 2. Extensor-flexor, the primary movement being that of extension, followed by a secondary flexor movement. This is common in the slighter forms of chorea and in nervous children; such twitches usually constitute the subsultus tendinum' so indicative of exhaustion in the course of typhoid fever. 3. Abductor-adductor twitches, the movements consisting in lateral separations of the fingers, followed by their being drawn together again.

The movements of the head—aside from those due to movements of the cervical spine—may be classified as those of flexion and extension; the bending forward and backward of the head; of rotation, in which the head remains erect; and of inclination or the depression of one or the other side. Flexion and extension of the head are of frequent necessity and physiological import; rotation is frequently necessary to move the eyes toward an object looked at, or to direct the ear toward a source of sound. Inclination is, I think, often of other significance: it sometimes indicates weakness, it is more frequently seen in young girls and weakly persons than in strong men. Inclination, with rotation to the same side, with slight flexion, is a position of the head very commonly seen in choreic girls, and then often accompanies an awkward, ill-balanced position of the spine. Inclination of the head, with rotation to the opposite side, and slight extension, is indicated by Sir Charles Bell in his figure in "Adoration." In seeking general information as to the signs of cerebral adequacy in an infant—that is, whether the infant has a good sound brain, probably capable of development—we always notice whether it can hold its head up, whether it usually keeps its head erect while sitting up.

Tooth-grinding, which is common in nervous children and among lunatics, champing of the jaws, and trismus, are signs of disordered conditions of the fifth nerve. The violent motions of the tongue seen in chorea and whooping-cough, the tremulous tongue of alcoholism and paralyses, indicate affections of the seventh nerve. Affections of the pneumogastric may produce palpitations, irregularities of organic action, the bronchial spasm of asthma, and functional aphasia.

It is a matter of very common experience that children and adult patients "hold themselves awkwardly"; stoop, or otherwise give the spine and trunk an ill-balanced position, due to want of nerve-muscular energy, and characteristic of the condition of exhaustion and weakness. Doubtless there is much expression in a torso; in many cases a weakly condition is indicated by a stooping attitude, with a lolling over to one side. It is difficult to indicate in precise terms the positions and movements of the spine, and perhaps this is one reason why so little is known about the action of the muscles of the back. With regard to the lower extremities, the gait and manner in walking may be characteristic of brain or cord disease. Conditions affecting the muscles of both lower extremities are usually dependent upon disease of the cord, and most of the signs by which spinal disease may be localized are derived from examination of the muscles of the legs. Reflex actions are also used as a means of localizing: and ascertaining the condition of the nerve-centers, and here, again, visible muscular conditions are the indices.

The significance of the action of muscles as indicating brain conditions has long been dwelt upon by writers. Camper, who wrote in 1821, has shown that the Laocoön presents evidence of how deeply the ancients had investigated the influence of pain as expressed in the figure and the muscles. Further on he quotes from the words of Paulo Somazzo's work, "Dell' Arte della Pittura," published in 1531, a passage describing the influence of the passions upon the muscles of the face, and still more minutely the different postures and contortions of the body. John Bulner, in his work entitled "Significative Muscles of the Affections of the Mind," published in 1649, expressed the opinion that every motion of the mind is indicated by a corresponding motion of the muscles, saying: When we assent, affirme, yield, grant, vote, confirme, confesse, admit, allow, or approve of a thing, etc., we are wont to nod or bend our head forward, the naturall reason of which motion in these, seems an approving, which is made by the Imagination, seeing, or hearing, somewhat done or said which accordeth very well, and this power remaineth in the Braine or forehead part of the head where in the cell and Seat of the Imaginations lieth. "When any of these things give it contentment, suddenly it moveth the same, and after it all the muscles of the body."

There is in the subject before us a field for observation and description in which the artist and the physician may work together, observing and analyzing, with as much exactness as may be, the mode by which the varying conditions of the brain and mind are indicated to our eye, and may therefore be described by words, and by drawing or sculpture. We must study man in all aspects of the case, and when we see in the face, limbs, or body indications of his brain or mental condition, we should analyze and describe—first, the position of features and parts as we see them, then the muscles which produce those positions or movements, knowing that the muscular condition which has produced the movements or positions is the result of the state of the corresponding nerve-centers. It has been said that a man's face is an index of his mind, and this is true; for all the varying changes of expression in the face (except those of color) are due to changes in the facial muscles, and these solely depend upon changes in nerve-cells. The knowledge that we already possess of the nerve centers is from observation of the condition of the muscles. In a given case, by comparing the state of the muscles during life as they may be affected with paralysis or spasm with the brain-lesion found after death, and by collecting and comparing many cases, it has been found that destructive or irritative lesions of certain parts of the brain cause paralysis or spasm of a certain set of muscles corresponding. It is probable, then, that by carefully continuing these methods of examination—that is, by describing with accuracy all states which are indicated by conditions of the muscles—we may add still more to our knowledge of the functions of different parts of the brain, and gain a further insight into the pathology of that large group of nervous centers termed functional.

  1. Abstract of articles published in "Brain."