study of the shoulder, the arm and one foot
Leonardo da Vinci's Notebooks
How it is necessary for the painter to know the inner structure of man.
The painter who has a knowledge of the nature of the sinews, muscles, and tendons will know very well in the movement of a limb how many and which of the sinews are the cause of it, and which muscle by swelling is the cause of the contraction of that sinew; and which sinews expanded into most delicate cartilage surround and support the said muscle.
In fifteen entire figures there shall be revealed to you the microcosm on the same plan as before me was adopted by Ptolemy in his cosmography; and I shall divide them into limbs as he divided the macrocosm into provinces; and I shall then define the functions of the parts in every direction, placing before your eyes the representation of the whole figure of man and his capacity of movements by means of his parts. And would that it might please our Creator that I were able to reveal the nature of man and his customs even as I describe his figure.
As regards the disposition of the limbs in movement you will have to consider that when you wish to represent a man who for some reason has to turn backwards or to one side you must not make him move his feet and all his limbs towards the side to which he turns his head. Rather must you make the action proceed by degrees and through the different joints, that is those of the foot, the knee, the hips and the neck. If you set him on the right leg, you must make his left knee bend inwards and his left foot slightly raised on the outside; and the nape of the neck is in a line directly over the outer ankle of the left foot. And the left shoulder will be in a perpendicular line, above the toes of the right foot. And always set your figures so that the side to which the head turns is not the side to which the breast faces, since nature for our convenience has made us with a neck which bends with ease in many
directions as the eye turns to various points and the other joints are Partly obedient to it.
Of human movement
When you wish to represent a man in the act of moving some weight, reflect that these movements are to be represented in different directions. A man may stoop to lift a weight with the intention of lifting it as he straightens himself; this is a simple movement from below upwards; or he may wish to pull something backwards, or push it forward or draw it down with a rope that passes over a pulley. Here you should remember that a man's weight drags in proportion as the centre of his gravity is distant from that of his support, and you must add to this the force exerted by his legs and bent spine as he straightens himself.
The sinew which guides the leg, and which is connected with the patella of the knee, feels it a greater labour to carry the man upwards in proportion as the leg is more bent; the muscle which acts upon the angle made by the thigh where it joins the body has less difficulty and less weight to lift, because it has not the weight of the thigh itself. And besides this its muscles are stronger being those which form the buttock.
The first thing that the man does when he ascends by steps is to free the leg which he wishes to raise from the weight of the trunk which is resting upon this leg, and at the same time he loads the other leg with his entire weight including that of the raised leg. Then he raises the leg and places the foot on the step where he wishes to mount; having done this he conveys to the higher foot all the weight of the trunk and of the leg and leaning his hand upon his thigh, thrusts the head forward and moves towards the point of the higher foot, while raising swiftly the heel of the lower foot; and with the impetus thus acquired he raises himself up; and at the same time by extending the arm which was resting upon his knee he pushes the trunk and head upwards and thus straightens the curve of his back.
There are [four] principle simple movements in the flexion per formed by the joint of the shoulder, namely when the arm attached to the same moves upward or downwards or forward or backward. One might say, though, that such movements are infinite. For if we turn our shoulder towards a wall and describe a circular figure with our arm we shall have performed all the movements contained in the said shoulder. And, since [every circle is] a continuous quantity, the movement of the arm [has produced] a continuous quantity. This movement would not produce a continuous quantity were it not guided by the principle of
continuation. Therefore, the movement of that arm has been through all the parts of the circle. And as the circle is divisible in infinitum the variations of the shoulder have been infinite.
The Tongue: Of the muscles which move the tongue
No organ needs so great a number of muscles as the tongue, — of these twenty-four were already known apart from the others that I have discovered; and of all the members moved by voluntary action this exceeds all the rest in the number of its movements.... The present task is to discover in what way these twenty-four muscles are divided or apportioned in the service of the tongue in its necessary movements which are many and varied; and in addition it has to be seen in what manner the nerves descend to it from the base of the brain, and how they pass into this tongue distributing themselves and breaking into ramifications. And it must further be noted how these twenty-four muscles convert themselves into six in the formation they make in the tongue. Moreover, you should show whence these muscles have their origin, that is some in the vertebrae of the neck... some in the maxilla, and some on the trachea.... And similarly how the veins nourish them and how the nerves give them sensation....
The tongue works in the pronunciation and articulation of the syllables which constitute the words. This tongue is also employed during
Study of the tongue
the necessary revolutions of the food in the process of mastication and in the cleansing there from of the inside of the mouth and teeth. Its principal movements are seven....
Consider well how by the movement of the tongue, with the help of the lips and teeth, the pronunciation of all the names of things is known to us; and how the simple and compound words of a language reach our ears by means of this instrument; and how these, if there were a name, for all the effects of nature, would approach infinity, together with the countless things which are in action and in the power of nature; and these man does not express in one language only but in a great number, and these also tend to an infinity; because they vary continually from century to century, and from one country to another, through the intermingling of the peoples who by wars and other mis-chances continually mix with one another; and the same languages are liable to pass into oblivion, and they are mortal like all created things; and if we grant that our world is everlasting, we shall say that these languages have been, and still will be, of infinite variety, through the infinite centuries which constitute infinite time. And this is not the case with any other sense; for these are concerned only with such things as nature continually produces; and the ordinary shapes of things created by nature do not change, as from time to time do the things created by man, who is nature's greatest instrument.
The Lips: Of the muscles which move the lips of the mouth
The muscles which move the lips of the mouth are more numerous in man than in any other animal; and this is necessary for him on account of the many action in which these lips are continually employed, as in the four letters of the alphabet bfmp, in whistling, laughing, weeping, and similar actions. Also in the strange contortions used by clowns when they imitate faces.
What muscle is that which so tightens the mouth that its lateral boundaries come near together?
The muscles which tighten the mouth thus lessening its length are in the lips; or rather these lips are the actual muscles which close them selves. In fact this muscle alters the size of the lip below other muscles, which are joined to it and of which one pair distends it and moves it to laughter,... and the muscle which contracts it is the same of which the lower lip is formed; and a similar process goes on simultaneously in
the upper lip. There are other muscles which bring the lips to a point; others that flatten them; others which cause them to curl back, others that straighten them; others which twist them all awry; and others which bring them back to the first position. So there always are as many muscles as correspond to the various attitudes of these lips and as many others that serve to reverse these attitudes; and these it is my purpose here to describe and represent in full, proving these movements by means of my mathematical principles.
Though human ingenuity may make various inventions answering by different machines to the same end, it will never devise an invention more beautiful, more simple, more direct than does Nature; because in her inventions nothing "is lacking, and nothing is superfluous. She needs no counterpoise when she creates limbs fitted for movement in the bodies of animals, but puts within them the soul of the body which forms them, that is the soul of the mother which first constructs within the womb the shape of man, and in due time awakens the soul that is to be its inhabitant.
Extracts from the Notebooks of Leonardo da Vinci
selected & edited by Irma A. Richter, Oxford University Press.