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THE PROPORTIONS OF A HUMAN ADULT
PLATES A AND B
CORRECTNESS of proportion is the first necessity of figure drawing, and therefore we must begin by considering the proportions of a human adult.
Figs. 1 to 4 are diagrams of a man, and Figs. 5 to 8 are those of a woman. In each set of drawings a similar arrangement of lines enclose spaces which have the given proportion to the height of the heads of the figures. It will be manifest that, by thus taking the height of the head as the unit of measurement and making the figure correct in proportion to it, we make all parts of the figure in due proportion to each other.
The average height of a man's head is 9 inches, and that of a woman is 8 inches. Scales in accordance with these measurements are given, by means of which the "full size" of any part of the diagrams may be ascertained. The block forms of the bones (except those of the head, hands, and feet) are shown. Therefore these diagrams enable us to compare the proportions of a man with those of a woman, and also to ascertain the size and position of the bones in each.
The male and the female figures are each shown as seven and a half heads high, but as the head of a woman is about half an inch less in height than that of a man, it will be evident that the woman has been represented as about three and a half inches shorter than the man, and this is the average difference in their heights.
The diagrams have, as far as possible, been made self-explanatory, and therefore no elaborate explanation of them is necessary ; but the student should particularly notice the position of the point at half the height of the figure (see Figs. 2 and 6); also that the line numbered 2 passes through the nipples and touches the lower corners of the blade-bones (scapulæ); that line number 3 is on a level with the top of the haunch-bones (innominate bones), and it also gives the position of the umbilicus in a man, but in a woman the navel is a little above this line; that when the arm is extended the elbow is half-way between the shoulder and the knuckle of the middle finger (see Figs. 4 and 8) ; and that in a standing figure the position of the knee may be ascertained by the method shown at A, B in Figs. 2 and 6. When testing the proportions of a figure all measurements should be taken from parts where the bones are subcutaneous, for if a person be either fat or thin the size of their bones will be the same, and only the fleshy portions of the figure will vary accordingly. The proportions of the head of an adult (which are the same in both sexes) are shown in Figs. 9 and 10. If the height of any required representation of the head of an adult be divided into eighteen equal parts, each part will represent half an inch in a man's head, and a trifle less in the head of a woman. Then the distance from the point of the chin to the lowest part of the nose (E to D), the height of the nose and of the ear (D to c), the vertical distance from the top of the nose to the lowest limit of the hair upon the forehead (C to B), will each equal five parts, and from A to B will equal three parts. Also if D, E be equally divided into three, the greatest prominence of the chin will be opposite the upper part of the lowest division, and the opening of the mouth will be on the line dividing the first from the second division. Then, if the length from C to D be divided into three parts as shown, the height of the wings of the nostrils will equal the lower division, and the position of the middle of the lower lid of the eye will be shown by the line between the two upper divisions.
The height of the head of an adult equals its length from front to back, and therefore in Fig. 9 the head has been drawn within a square. The front of the ear at X is half-way between the tip of the nose and the back of the head.
The greatest width of the head (exclusive of the ears) equals two-thirds of its height (see Fig. 10); if this width be divided into five equal parts, the distance across the wings of the nostrils and the widths of the openings of the eyes will each equal one division.
The method of "setting" out a head, shown in Figs. 9 and 10, is very useful for large work, but it is more convenient to "set out" small drawings, by the method shown in Fig. 11, as follows: Bisect the height of the head to find the position of a line that will pass through the inner corner of the eye (A); take a point a little above A or the upper limit of the nose (B); the length of the nose may then be found by equally dividing the distance between B and c, and the position of the other parts of the head may be obtained by applying the information given in connection with Figs. 9 and 10.
Fig. 12 shows that the height of an adult when standing erect equals the distance between the finger-tips when the arms are extended horizontally; and also that the limbs move in circles which have their centres at the joints. From Fig. 13 it will be seen that in a sitting figure the distance from the top of the head to the seat equals four heads. This diagram has been left at the "blocking out" stage to show how a drawing of a figure should be commenced.
When studying this set of proportions we must remember they are average measurements, and therefore it will be possible to find both in "antique" sculpture and in life models instances of slight differences in proportion from those given here. But it is these slight variations from the average which give individual character to a figure, and therefore by using the given set of proportions as a test when drawing from the "life" or the "antique," we shall be enabled to at once perceive the peculiarities of the figure we are representing. When drawing figures without the aid of a "model," a set of proportions is the greatest safeguard against gross errors that it is possible to have.
DEFINITIONS OF THE PRINCIPAL TERMS USED IN DESCRIBING THE ANATOMY OF THE HUMAN FIGURE
Many ordinary words when used in anatomical descriptions have a restricted technical sense, and therefore it becomes necessary to define their meaning when thus used.
The normal attitude is the position assumed by a person when standing erect, with the feet together, the arms extended and close to the body, and the palms of the hands turned forwards. Unless it is stated to be otherwise, the figure is always supposed to be in the normal attitude when it is being described for anatomical purposes.
The mesial plane is an imaginary plane by which the figure is supposed to be divided into two lateral halves : the middle line is the line in which this plane meets the surface of the figure.
Internal and external denote distance from the mesial plane; that which is nearer the plane being said to be internal to that which is farther from it.
Superficial and deep indicate position with regard to the surface of the figure; thus, a muscle which is near that surface is described as superficial to a muscle which underlies it.
In anatomical descriptions the upper limb is generally called the upper extremity, the part of it which extends from the shoulder to the elbow being known as the arm, and the part between the elbow and the hand as the forearm.
The lower limb is frequently referred to as the lower extremity, the portion which extends from the body to the knee being called the thigh, and the part between the knee and the ankle the leg.
The sole of the foot is generally called the plantar surface. The dorsum of the foot is the surface which is uppermost when the sole of the foot is on the ground.
The above are the principal terms used in anatomical descriptions of the human figure, but there are a few others which will be defined as we proceed.
THE HUMAN SKELETON: ITS ELEMENTS, ITS JOINTS, ITS FITNESS FOR THE ERECT ATTITUDE
Zoologists place man in that great division of the animal kingdom called vertebrata, the chief characteristic of which is that all the animals contained in it have an internal skeleton or bony framework by which the external soft parts are supported. The combined hardness and elasticity which so wonderfully adapts bone for the construction of the skeleton is due to its chemical composition. It consists of about sixty-six parts of earthy matter (chiefly phosphate and carbonate of lime) and thirty-four parts of an animal substance called ossein (which may be converted into glue by boiling). The existence of these substances in bone can be easily demonstrated, for if a bone be carefully burnt the animal matter will be destroyed and the fragile residue will retain the shape of the bone; but if a bone be steeped in diluted muriatic acid the earthy portion will be dissolved, and the ossein, still retaining the form of the bone, will remain, and it is so elastic that it may be bent in any manner, and it will recover its original shape if allowed to do so.
Bones are composed of an outer hard layer called the compact tissue and an inner portion named the cancellous tissue, and within some bones there is a space (known as the medullary cavity) which is filled with marrow. Bones are nourished by bloodvessels, etc., which ramify through numerous small channels in their substance.
In some parts the bony framework of the skeleton is completed by the addition of an elastic substance technically called cartilage, but generally known as gristle.
The various parts of the skeleton are connected by joints, of which there are five different varieties.
1. Sutures, which are immovable joints formed somewhat like the "dovetailed" joints used in woodwork; they are found in the head only.
2. Planimetric or gliding joints, in which slight movements are produced by the parts gliding upon each other, as in the vertebrae and in the arch of the foot.
3. Hinge joints, which allow of motion to and fro but not of lateral movement, as at the elbow, and at the second and third joints of the fingers.
4. Ball-and-socket joints, which permit of circumduction—i.e., the slight movement of one end of a bone in its socket while the other extremity is made to describe a circle—as at joint of the hip and of the shoulder.
5. Pivotal joints, in which the bone rotates as upon a pivot; this is a movement peculiar to the radius, and it will be explained later on.
At the movable joints the surfaces of the bones are coated with cartilage, and a fluid called synovia (which resembles the white of an egg) is secreted by a membrane which encloses the joint ; thus the joint is lubricated. These joints are strengthened by bands of glistening fibres named ligaments, but as the ligaments are mostly so thin that they do not affect the external form of the figure, they seldom demand the attention of an artist. In the action of the muscles upon the skeleton the force employed usually operates after the manner of levers, the fulcra being situated at the movable joints, as shown in Figs. 1 to 3.
The first order of levers has the fulcrum (F) between the power (P) and the weight (w) as shown at A. There is a lever of this kind at the junction of the head and the vertebral column (see Fig. 1), where the anterior part of the head (which is heavier than the posterior part) is the weight, the joint is the fulcrum, and the trapezius muscle (a) and other muscles that act with it are the power. In levers of the second order the fulcrum (F) is at one end of the lever, the power (P) at the other, and the weight (w) is between them (as shown at B). A lever of this kind is seen in the foot if a person is "standing on tip-toe," when the ground becomes the fulcrum, the figure the weight, and the muscles at the back of the leg (b) supply the power (see Fig. 2).
Levers of the third order have the power (P) between the fulcrum (F) and the weight (w), as shown at C. In the human figure this kind of lever is found where rapid movement is essential, as at the elbow-joint (see Fig. 3), where the hand, etc., is the weight, the elbow is the fulcrum, and the muscle at C is the power.
From the feet to the head the complex skeleton of man clearly displays fitness for the erect attitude. The feet are broad, strong, and large in proportion to the other parts of the figure, and are placed at right angles to the leg in such a manner that a man can stand firmly and move freely when erect. The legs and thighs of man are very long in proportion to his body, which enables him to take long strides when erect. His upper limbs are not equal in length to his lower limbs, and therefore a man finds it difficult to "walk on all fours." When erect the attitude of his head gives him the advantage of a range of vision he would not possess if he were limited to the usual movements of a four - footed animal. Further, man experiences no difficulty in assuming and maintaining the erect posture, and therefore we may reasonably suppose it to be natural to him.
(The numerals in the margin are references to the Plates.)
The bones of the head and face are called the skull. It is divided into two sections ; one is called the cranium, and one the face. In the cranium there are eight bones—1 Frontal, 1 Occipital, 1 Sphenoid, 1 Ethmoid, 2 Parietal, and 2 Temporal.
These are joined together at their edges by either overlapping and rough partly jointed plates, or by a system of dovetailing into one another. These junctions are called Sutures.
1. The Frontal Bone, or bone of the forehead, forms the upper and fore part of the head ; it extends a little towards the temples, and forms also the upper part of the socket of the eye.
IV.A ii.—II. i.
2. Occipital Bone is so called from its forming all the occiput or back of the head; much of this bone forms the base of the skull, and lies in the neck so deeply as to be hidden by it.
3. Sphenoid Bone is a large irregular bone placed across the skull between the occipital and the ethmoid bones; it lies over the top of the throat, so that its processes form the back of the nostrils and roof of the mouth ; it is so placed as to support the very centre of the brain.
4. Ethmoid Bone, like the last, lies in the base of the skull, and is invisible in the living form; it is a small square bone and a mass of cells. It lies over the nose, and is an important part of that organ ; it supports a part of the brain. The nerves that supply the nose pass through it at many points and perforate it like a sieve ; it takes its name from this perforated or ethmoid plate.
5 and 6.—The Parietal Bones are two large and flat bones which form the sides and upper part of the head ; they are the walls or sides of the cranium.
I.—II. iv.—III. i.
7 and 8. The Temporal Bones form the lower parts of the sides of the cranium. They are called temporal from the hair that covers them being the first to turn grey, marking the advance of life.
The sutures for our purposes are usually reckoned as seven in number. They are serrated seams between the bones.
1. The Coronal Suture is that which joins the frontal to the parietal bones ; it extends almost directly across the head from ear to ear ; it descends behind the eye into the deep part of the temple, and there losing its serrated appearance, becomes like the squamous or scaly suture at the edge of the temporal bones. It is named coronal because, it is said, the ancients wore their garlands on this part of the head.
2. The Lambdoidal Suture is that which joins the parietal to the occipital bone. It begins behind one ear, ascends and arches over the occiput, and descends behind the other ear. It thus strides over the occiput in a form somewhat resembling the letter Lambda, A, of the Greeks, hence its name.
3. The Sagittal Suture joins the parietal bones together; it runs on the very top of the head, and extends forwards from the lambdoidal suture till it touches or sometimes passes the coronal suture, and from lying between these two sutures, like an arrow between the string and the bow, has been named sagittal.
4. The Temporal Sutures join the temporal bones to the parietal, occipital, and by the sphenoid to the frontal bones. The sphenoid enters into the temporal suture just behind the eye. It describes an arch corresponding almost with the arch of the external ear, and meets the coronal suture an inch before the ear, and the lambdoidal an inch behind it. The edge of the temporal suture is thin, and like scales of armour as to its overlapping; it is called on this account the squamous or scaly suture.
Excerpted from The Complete Guide to Artistic Anatomy by John C. L. Sparkes, William H. Gates. Copyright © 2010 Dover Publications, Inc.. Excerpted by permission of Dover Publications, Inc..
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