Anatomy of the Human Head |
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Free Art Book for Learning Human Anatomy The HeadFor so long a time has the oval been used as the basis for the construction of the human head and face that the use of the block or cube seems quite revolutionary. Yet for many reasons the cube seems preferable. The oval is too indefinite, and offers no points for comparison, no basis for measurement. The eye does not fix on any point in a curved line. On the ground plan of a square, however, any form may be built. The block moreover carries with it from any angle its perspective and its foreshortening, and it carries with itself the sense of mass. Especially does it carry with itself the important element of the bilateral symmetry of the head -- a symmetry that is present indeed in all living things. A vertical line in the centre divides the head or the trunk into parts equal, opposite, and complemental. The right eye is the counterpart of the left; the two halves of the nose are symmetrical; How to construct such a block? Camper, Professor Bell, and others have studied innumerable human skulls trying to discover some constant measurement by which to classify them as ancient or modern or according to race. They finally fixed upon two lines with the angle between them. The first passes from the base of the nose to the roof of the ear canal; the second passes from the upper incisor teeth to the prominent part of the forehead. The angle between these lines is practically constant for a given race or a given age of evolution. Individual variations occur, but they are less than the standard. This angle is less in the older and less evolved races, and the vertical line approaches nearer the perpendicular in the newer races, especially the Caucasian. In the classical Greek head it even passes the perpendicular, although no actual Greek skulls in which this is the case have ever been discovered. This angle, in the Caucasian races, is about eighty degrees. It is not easy to construct a block on such an angle, and it is very desirable to have a right angle. By dropping the horizontal line at its rear end from the roof of the ear canal to the tip of the ear lobe, and by drawing the vertical line from the base of the nose where it joins the upper If on these straight lines a cage be built, bounding the head and face, it will be found that the front and back are oblong and the sides are square. The top of the cage should be level with the top of the head, the bottom with the bottom of the chin; the border of the cheek should fit the sides. The length of the oblong front will equal one and three-quarters times its width. The cheek bones set back from the front of the cage about one-third of the distance to the ear.
Eminences, Ridges and Depressions of the Skull
The Angles of Construction
Muscles of Mastication:1 Temporal. 2 Masseter. 3 Buccinator (cheek muscle). 4 and 5. Lesser and greater zygomaticus (muscles of expression).
Construction Lines in PerspectiveMASSES Into the rounded mass of the cranium sets the narrower mass of the forehead bounded by the temples at the sides and by the brows below. From the lower outer corners of the forehead the wedge of the cheek bones begins; moves outward and downward until it just passes the curve of the cranium, then down and in, in a long sweep, to the corner of the chin. Outside of and behind this lower line is another wedge, that of the corner of the jaw, with the line itself for base, and a very low apex. The two cheek bones form together the central mass of the face, in the middle of which rises the nose.
PLANES The plane of the forehead slopes upward and backward to become the cranium; and the sides turn sharply to the plane of the temples. The plane of the face, divided by the nose, is broken on each side by a line from the outer corner of the cheek bone to the center of the upper lip, making two smaller planes. The outer of these turns to become the plane of the jaw, which also is again divided by a line marking the edge of the masseter muscle, running from the outer border of the cheek bone to the corner of the jaw; and again making two secondary planes, one toward the cheek and one toward the ear. The relations of these masses and planes is to the moulding of a head what architecture is to a house. They vary in proportion with each individual, and must be carefully compared with a mental standard. THE HEAD -- PROFILEIn profile the masses of the head are the same -- the cranium, the skeleton of the face, and the jaw. The front border of the temple is seen to be a long curve, almost parallel to the curve of the cranium. The top of the cheek bone is seen to be prolonged backward toward the ear as a ridge (zygoma or yoke) which also marks the base of the temple. It slopes slightly down in front. From cheek bone and zygoma, where they meet, a lesser ridge is seen rising between the temple and the orbit, marking the back of the orbit and the first part of the long line of the temple. PLANES The planes and divisions of planes of the face are the same as in the front view, in different perspective.
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