Cephalic Index and Physical Anthropology

Quoted text

From: Race and People

By William C. Boyd Ph.D. and [Isaac Asimov? Isacc Asimov Ph.D.]

Copyright 1955 Abelard-Schumann, New York

From and anthropologists' viewpoint the particular set of bones most often measured for purposes of racial classification are those of the head. As seen from above, the head has an oval shape, which is longer in one direction (from front to back) than in the other (from side to side). If the front-to-back length of the head is called 100, then the side-to-side width is equal to some smaller figure. If the width were three-quarters of the length, it would be 75; if it were four-fifths of the length, it would be 80.

The width of the head in relation to the length is known as the cephalic index. Naturally, the cephalic index is different for different people. People with a cephalic index of less than 75 have long, narrow skulls, as seen from above, since the width of the skull is less than three-quarters of its length. People with skulls of this shape are called dolichocephalic, which is simply Greek for "long-headed." If the cephalic index is more than 80, the head appears to be short and broad, as seen from above. People with skulls of this shape are called brachycephalic, which is the Greek for "short-headed." A cephalic index between 75 and 80 makes a head mesocephalic, which is Greek for "medium-headed."

Groups of people can differ from one another in head shape. The peoples in northwestern Europe, including the inhabitants of Scandinavia, Great Britain, Holland, Belgium, and the northern portions of France and Germany, are medium-headed, on the average. The peoples farther south, in central France, southern Germany, and northern Italy (as well as almost all the people of eastern Europe) are short-headed. Still farther south, along the Mediterranean, in Portugal, Spain, southern France, Italy, and the Balkans, the people are medium-headed. In North Africa and the Middle East many long-heads are found.

Figure 1: Dolicocephalic head (left), Mesocephalic head (center), Brachycephalic head (right)

Using such skull measurements as a guide, some people have attempted to divide the "White Race" into three sub-races. The people of northwestern Europe they call Nordic. These are light-complexioned medium-heads. The people of central and eastern Europe are Alpine. These are dark-complexioned short-heads. Finally, the people of southern Europe and northern Africa are Mediterranean. These are dark-complexioned medium-heads and long-heads.

Under such a system, some European countries would be inhabited mostly by one such "sub-race." For instance, Norway would be almost entirely Nordic, Hungary almost entirely Alpine, and Portugal almost entirely Mediterranean. Other countries would be made up of two or even three "sub-races." Germany contains both Nordics and Alpines. Italy contains both Alpines and Mediterraneans. France, which has a population that is quite uniform culturally, would be made up of all three of these "sub-races."

Figure 2: Races of Europe, North Africa and the Middle East, on the basis of head shape

Head shapes vary outside the "White Race" too. Most members of the "Black Race" are long or medium-headed and most members of the "Yellow-Brown Race' are short-headed.

The shape of the head, like height, can vary with the diet. Children born during a long northern winter are deprived of sunlight during the early months of their lives. Unless they are given cod-liver oil or some form of vitamin preparation, they are apt to be lacking in Vitamin D. When this happens, the children suffer from a disease known as rickets, in which bones do not harden properly. The too soft skulls of such children may then become misshapen from the pressure of the cradle, and skull measurements in later life won't mean much.

Quoted text

From the Catholic Encyclopedia

As regards the skeleton the attempt was made, in the first place, to determine racial peculiarities by the study of the skull. The length, breadth, and height of the cranium were determined, and from these were calculated the length-breadth, length-height, and breadth-height indices -- that is, the breadth and height were expressed as percentages of the length or breadth. According to the Frankfort Agreement of 1882 skulls are divided into narrow or dolichocephalic (up to 74.9), medium or mesocephalic (75.0 to 79.9), and broad or brachycephalic (over 80.0); and further into low or chamaecephalic (up to 70.0), medium or orthocephalic (70.1 to 75.0), and high or hypsicephalic (over 75.0).

According to the international agreement of 1883 the following designations were added to those already in use: ultradolichocephalic (55.0 to 59.9) hyperdolichocephalic (60.0 to 64.9), hyperbrachycephalic (85.0 to 89.9) and ultrabrachyhcephalic (90.0 to 94.9). The French call skulls with a length-breadth index of 75.01 to 77.77 subdolichocephalic, of 80.01 to 83.33 subbrachyceplhalic; only the indices 77.78 to 80.0 are looked upon by them as mesocephalic. For the front of the skull the criteria used in determining the peculiarities of a race are the height and breadth, the facial angle, and the form of the nostrils, orbital entrance, and palate. The ratios of the breadth of the zygomatic arch (supposing it equal to 100) to the height of the entire face (from the nasion to the gnathion), and to the height of the upper face (from the nasion to the prosthion), give facial indices which are divided by R. Martin into the following groups: (1) Index for the entire face: hypercuryprosopous (to 79.9), curyprosopous (80.0 to 89.9), leptoprosopous (90.0 to 94.9), hyperleptoprosopous (over 95.0). (2) Index for the upper face: hypereuryonic (to 44.9), euryonic (45.0 to 49.9), mesial (50.0 to 54.9), leptous (55.0 to 59.9), hyperleptus (over 60. 0).

The expressions euryprosopous and euryonic correspond to the chamaeconchous of the Frankfort Agreement; leptous is the same as leptoprosopous. According to the Frankfort Agreement the orbits are chamaeconchous (to 80.0), mesoconchous (80.1 to 85.0), hypsiconchous (over 85.0); the nostrils are leptorhine (to 47. 0), mesorhine (47.1 to 51.0), platyrhine (51.1 to 58.0), hyperplatyrhine (over 58.0); the palate is leptostaphyline (to 80.0), mesostaphyline (80.0 to 85.0), brachystaphyline (over 85. 0). The facial part of the skull with a facial angle up to 82 is called prognathous; with an angle of 83 to 90, orthognathous; with an angle of 91 and over, hyperorthognathous.

By facial angle is meant that formed by the line connecting the naso-frontal suture and the point farthest forward on the upper jaw between the central incisors (the alveolar point) with the German horizontal plane. The German horizontal plane passes through the lowest point of the under edge of the orbits and the upper edge of the ear-aperture. Besides these indices, to which correspond groups more or less generally recognized, other points of importance for the shape of the braincap and the facial part of the skull are: the ratio of the greatest breadth of the braincap to the smallest frontal breadth (small distance between the temporal lines over the zygomatic process of the frontal bone); also the ratio of the breadth of the zygoma to the smallest breadth of the forehead, and to the breadth of the face at the two angles of the lower jaw. At the base of the skull measurements can be taken of the angle formed by the plane of the occipital foramen with the German horizontal plane, and of the angle formed by this German plane with the surface between the occipital foramen and the spheno-basilar joint.

In the comparison of crania, especially of the ratios of angles, it is necessary to place the skull in a definite position. To attain this, various methods have been used besides the German horizontal plane already mentioned. G. Schwalbe has recently used the glabella-inion line (glabella, the central point between the arches of the eyebrows; inion, the protuberance of the occiput at the median line) for the comparison of the brainpans at the sagittal sutures, while H. Klaatsch has returned to the glabella- lambda line formerly proposed by Hamy (lambda, the point of union of the lambdoid and sagittal sutures). In the first case the height of the cap (the distance of the highest point from the glabella-inion line), the height of the bregma (the linear distance of the bregma from the point of comparison, i. e. the distance between the point of intersection of the coronal and satittal sutures by the glabelle-inion line), and their ratios to the glabella-inion line (which is taken as 100), can be determined. On this line Schwalbe traced the frontal angle (that between the tangent of the frontal bone at the glabella and the glabella-inion line), the bregman angle (bregma-glabella-inion); the lambda angle (lambda-inion-glabella); the opisthion angle (glabella-inion- opisthion; the opisthion is the posterior border of the occipital foramen). Schwalbe also determined the position of the bregma (distance of the base point of the bregma-verticals from the glabella) and the index of this position to the glabella-inion line, the glabella-cerebral index (ratio of the tendon of the glabella arch to the tendon of the arch of the frontal bone). The other bones of the skeleton were not made the object of exhaustive study until more recent times. Particular attention should be made, as important in the comparative anatomy of races, of the cross-section of the diaphysis of the long bones, and of the position of the epiphyses to the diaphysis.

Not only the structure of the skeleton, but also the musculation and the general formation of the soft parts are taken into consideration. As regards the musculation attention is given especially to the varieties found in the face; measuring the thickness of the soft parts of the face (by piercing with needles such parts in fresh or preserved cadavers) also yields good results, when there are sufficient subjects for investigation. Apparently, the flat, broad face of the Mongol is mainly conditioned by the great thickness of the soft parts in the region of the cheek. Racial differences are also shown by the nose. The nose of Europeans and Asiatic Indians is long, narrow, with a more or less decided projection; the roots are high and narrow, the back straight or convex, the wings are appressed, the nostrils set vertically to the upper lip, the elevation (that is the height of the point above the lip) relatively large.

According to Topinard's theory noses are divided into aquiline, straight, flat, hooked, and Semitic noses. The nose of the aboriginal Australians is poorly developed; it does not project, the roots are low and broad, the back broad and rather concave, the wings decidedly projecting; the nostrils lie parallel to the upper lip, and the elevation is slight. There are a large number of intermediate forms between these extreme ones (e.g. according to Topinard, the Mongoloid, negroid, and Australioid). The roots of the nose may enter the forehead without depression, by a sharp bend, or in a flat curve. The region above the orbits and between the borders of the orbits varies. Either the entire part projects in a ridge (brow ridges, torus supraorbitalis), or only the glabella, that is the prominent part of the forehead just above the root of the nose, seems to be curved, or projections arise from a somewhat depressed glabella and extend to about the middle of the upper orbital border, the sections on the sides being then flat (planum supraorbitale). The forehead is either flat and receding, or is full, domed, and rises more or less abruptly. The position of the sockets of the eyes if horizontal in the white race and inclines obliquely upwards in Mongols; in the latter case the lacrimal caruncle is generally not free, but is covered by a fold that inclines downward in a curve (the Mongolian fold). In the same way the edge of the Mongolian eyelid, which in other cases is free, generally lies under a transverse fold. The forms of the ear and mouth are less used as racial characteristics. They display only individual variations, although a peculiarity of the negro race is the great protrusion and thickness of the lips.

Especially important for the differentiation of races are the colour of the eyes and skin, and the form and colour of the hair. The colour of these parts of the body is conditioned by a brownish pigment, on the amount and seat of which the shade of colour depends. Eyes are called blue and blue-grey when only the black layers of the iris contains the pigment, which appears blue through the cloudy outer layers of tissue. If the other layers of the iris also contain pigment, the eye appears from light to dark brown. The pupils are like a dark circle, the blood-vessels of the retina appearing red only in albinos (persons with very little or no pigment). The other parts of the eye also contain more or less pigment. The pigment of the skin is found chiefly in the epidermis: in new-born children of coloured races (at times also in white infants), as the Mongolians and negro, pigment in the true skin or corium produces blue spots in the region of the loins, called the blue Mongolian spot. In hair the horny outer portion is the main seat of the pigment. Besides the amount of air in the hair is also of importance; hair containing a great amount of air (appearance of age) looks grey or white, this condition being usually accompanied by a disappearance of the hair-pigment. Hair is divided as to colour into flaxen, light brown, black, red, and grey; it is lank, smooth, wavy, or curly. Lank hair generally shows a round cross-section, and curly an oval one; there are other cross-sections (e.g. the reniform or elliptical). In the same individual the eyes, hair, and skin may be of different colours. Blue eyes, flaxen hair, and white skin constitute the blonde type; brown eyes, brown hair, and dark skin make the brunette type. Between these two types are all possible variations and mixtures.

Although the human race must be regarded as a unit intellectually and physically, there have existed and still exist differences which permit a classification into various groups and races. Even the most ancient remains of man, dating from the glacial period in Europe, show differences that justify the acceptance of at least two races. Remains of skeletons that certainly belong to the Quaternary age have been found in France, Germany, and Austria. The shape of the crania found at Spy, Krapina, La Chapelle aux Saintes, Le Moustier, etc., resembles that of the skull discovered at Neandertal, the geological stratification of which is uncertain. These remains can be grouped together as the "Neandertal race", which had a long, narrow, low skull with very retreating forehead, enormous brown ridges (torus supraorbitalis), powerful masticating apparatus, upper jaw with the fossae caninae, heavy under jaw with broad ascending branch, no chin, and chin part with an outward convex curve. Some of these characteristics are still to be found among the Eskimo and aboriginal Australians. The bones of the skeletons indicate a bulky, relatively low-sized frame. The gait was upright, but it would seem with knees somewhat bent. Variations existed even in this era. The Krapina remains belong to crania somewhat broader than do the remains of the Neandertal race of Western Europe. The strata in which the remains of the skeletons were found must be regarded as belonging to the last warm intermediate period (or the last glacial period), and were found with remains of the early Palaeolithic period, the stage of civilization represented by the Saint-Acheul and Le Moustier remains.

During the glacial period, particularly during the late Palaeolithic period (as represented by the remains found at Aurignac, Solutr�, and La Madeleine), human beings of a different form existed. Their remains, as those found at Laugerie-Basse, Chaneclade, Mentone, and Combe-Capelle, may be grouped together as the "Cro-Magnon Race". The peculiarities of the Neandertal race are not to be found; the generally long dolichocephalic crania have a good vault, and are relatively high without great brow ridges; the apparatus for mastication is less powerful; the upper jaw contains plainly fossae caninae; the under jaw is less massive, the chin being fine and projecting.

In the structure of the cranium the Cro-Magnon race on the whole resembled the modern European. Local variations are recognizable. It is not impossible that both diluvial races lived at the same era, so that crossing appeared, as would seem the case from the skulls found at Galley Hill and at Br�nn. The bones of the skeletons indicate a higher stature. Variations with a broader skull appeared in Europe very soon after this, if not along with the long-skulled Cro-Magnon race in the diluvian epoch, so that the present different shapes of crania found in Europe seem to go back to the earliest era. Schliz ascertained two main forms of crania in the remains found in a layer of the Ofnet cave near N�rdlingen (Bavaria) belonging to the transition period between the Quaternary and the present geological era: one was a low, short skull and the other a moderately high, long skull, both with a low, broad face. These skulls recall, on one hand, the form of the skull of the homo alpinus, and, on the other, the structure of the skull of the later lake-dwellers and of the Mediterranean type.

While in the course of the prehistoric epochs in Europe the variations in the form of the skull multiplied, Schliz believes that the various prehistoric ages (Stone age, Bronze age, Iron age) show races with well-defined forms of the skull. At present time the European, of all the branches of mankind, has been the most thoroughly investigated anthropologically. Notwithstanding the crossings which have occurred continuously for centuries, certain groups with definite somatological peculiarities are recognizable. Stature, the shape of the skull, and the colour of the complexion have been taken as the criteria of these groups. According to this classification there is in the interior of Europe, in Alpine territory, a brunette population of medium stature and with a broad head; toward the north the crania are narrower, the colour of the skin, hair, and eyes is lighter, the stature is higher; towards the south the stature decreases, the complexion is darker, but the skull in the south, as in the north, is narrower than in the case of the first-named class. Starting from the north to the south, Ripley names these three types;

(1) Teutonic race: long head and face, very light hair, blue eyes, high stature, narrow and partly curved nose;

(2) Alpine race: round head, broad face, light chestnut brown hair, nut-brown eyes, robust medium stature, variable but generally broad, strong nose;

(3) Mediterranean race; long head, long face, hair dark-brown to black, dark eyes, medium to small stature, rather broad nose. Between these pure types there are innumerable crossings.

It is exceedingly difficult, if not impossible, to include the various races of mankind in one system. All attempts made hitherto contain certain defects which are perhaps unavoidable. Linnaeus sought to establish the characteristic physical and intellectual peculiarities of the inhabitants of the four quarters of the globe then known. Later investigators have selected one or a few peculiarities of the body (e.g. the shape of the cranium or hair, the colour of the skin) as the principle of classification, or have used a combination of several characteristics. Finally ethnological peculiarities (especially the language and degree of civilization) were invoked for aid in characterization. Linnaeus differentiated four varieties of the homo diurnus (a sub-division of the homo sapiens): (1) American; (2) European; (3) Asiatic; (4) African. Not only were the colour of the skin and eyes, the colour and form of the hair, and the form of the nose used as criteria of these four divisions, but the different temperaments of the four races were also distinguished, other criteria being their peculiarities of character, mode of dress, and whether the individual races were governed by customs, laws, beliefs, or arbitrary rule.

Blumenbach already attempted to group the races of mankind on the basis of purely somatological peculiarities, selecting five typical forms of the cranium as the criteria of the five races of men. He took as the normal type the skull of the Caucasian race, which is distinguished by harmony of the individual parts, none being unduly prominent: with roundness (mesocephaly) are united a massive high forehead, narrow cheek-bones, round alveolar arch, and an orthognathous upper jaw.

To the Caucasian type belong: European (except the Lapps and Finns), Western Asiatics, and North Africans. Around this type are grouped the others, which are related both to it and one another.

The Mongolian race includes most Asiatics, the Finnish tribes, the Lapps and the Eskimo; it has an almost square skull (exceedingly brachycephalic), flat nose, flat projecting malar bone, somewhat broad alveolar arch, and projecting chin.

The American race has a higher forehead, highly developed superciliary arch, deeply sunken bridge of the nose, cheek-bones strongly projecting sidewards, and high, broad, and strong lower jaw. In this race Blumenbach included all aboriginal Americans except the Eskimo. The skull of the Malay race is brachycephalic; the parietal bones project strongly sidewards, the nose and cheek-bones are flat, and the upper jaws slightly prognathous. To this race belong the inhabitants of Malacca in Asia and the natives of the islands of the Pacific and Indian Oceans.

The Ethiopian race includes the inhabitants of Africa except the Caucasian Africans in the north; the skull is dolichocephalic, the forehead full, the cheek-bones prominent, the nostrils wide, the alveolar arch narrow and prominent, the jaws prognathous, and the lower jaw large and strong. Blumenbach added to these craniological criteria others of a general somatological character, deduced from the observation of the members of the body, chiefly of the head and its parts.

Blumenbach's classification still has adherents, B. P. Ehrenreich, for example, being a vigorous supporter of it. He adds to the classification, however, those races that have become known or at least better known since Blumenbach's time. These are mainly the blacks of Asia and the aboriginal races of Augstralia and Oceania. According to Ehrenreich, the classification is: (1) Caucasian- Mediterranean; (2) African-Nigritian; (3) Mongolian; (4) American; (5) Malay Polynesian; (6) Australian. In addition there is (7) the Papuans and the blacks of Asia, including the Dravidians and the Kolarian tribes of India, whose position in Ehrenreich's anthropological system must still be regarded as uncertain. Blumenbach's classification was based on observation and description. There now followed a series of attempts to determine the different types of measurements. For the determination of the variations in the facial part of the skull Camper had already settled by measurement the facial angle, that is the angle made by the profile line and auriculo-subnasal line (the line from the ear orifice to the lowest part of the nose). A. Retzius introduced the word orthognathism to signify an almost right facial angle (90�), and called the more acute facial angle prognathy. Having noticed that in Sweden the Germans had narrow skulls, while the skulls of the Lapps were broad, Retzius sought to determine these shapes mathematically by the length-breadth index. He combined the groups of dolichocephalic and brachycehalic crania gained in this way with the groups of facial angles, and thus arrived at four main types of crania: orthognathous dolichocephalic, orthognathous brachycephalic, prognathous dolichocephalic, and prognathous brachycephalic. However, this classification of the shapes of the cranium was unsatisfactory, even when mesocephalic crania were separated from the others, since the various forms appear within every race, although perhaps with varying frequency. Welcker's investigations proved that crania ranging from dolichocephalic to hyperbrachycephalic are found in the Mediterranean, Malayan, and American races; the Monoglians appear to be rather mesobrachycephalic and hyperbrachycephalic, while the black races incline more to dolichocephaly. J. Kollman also based his racial classification on the shape of the skull and face. He supposed six sub-species: chamaeprosopous dolichocephalic, chamaeprosopous mesocephalic, chamaeprosopous brachyhcephalic, leptoprosopous dolichocephalic, leptoprosopous mesocephalic, leptoprosopous brachycephalic. These sub-species have, through migrations and penetrations, spread over the entire world, and may be grouped into eighteen varieties according to the nature of the hair (smooth, bristly or coarse, and woolly).

Besides the shape of the skull, other somatological peculiarities have been employed by

P. Topinard in the classification of races. Following Cuvier's classification, he takes as his main divisions the white, yellow, and black races, which he characterizes mainly by the shape of the nose. The narrow-nosed (leptorhine) white race has wavy hair with oval cross-section. Of those with dolichocephalic crania, one division is blond and large (Anglo- Scandinavian or Cymric); another large with red hair (first type of the Finns); a third brunette and relatively small (Mediterranean races). The mesocephalic type with brown hair and relatively small stature is found in the Semites and Egyptians. The brachycephalic type is composed of the little Lapps and Lagurians with brown hair, and the Celto-Slavs of medium height. The yellow race with nose of medium width (mesorhine), coarse, straight hair of round cross- section, also contains dolichocephalic, mesocephalic, and brachycephalic types.

The Eskimo are small, dolichocephalic, and have a yellow skin; the Tehuelches are large, dolichocephalic, and have a reddish skin; the Polynesians are large, mesocephalic, and have a reddish skin. The brachcycephalic type is represented by the Quaranni and Peruvians, the former being of medium size with yellow skin, and the latter small with olive skin. The broad-nosed (platyrhine) black race was divided by Topinard into one group with straight hair of oval cross-section, and a second group with a woolly hair of elliptical section. The first group, comprising the aboriginal Australians, are dolichocephalic, tall, and have a black skin; all three types of skull appear in the second group. The very small yellowish Bushmen, the large black Melanesians, and the African negroes are dolichocephalic, the medium-sized black Tasmanians mesocephalic, the small black Negritos brachycelphalic.

Huxley classified mankind on a somatico-anthropological basis. He divided the human race into four main types: the Australioid, Negroid, Xanthoeroi, and Mongoloid, to which he afterwards added the Malenochroi. The aboriginal Australians are the chief representatives of the dolichocephalic Australioid type (dark skin and eyes, wavy black hair, flat nose, pronounced osseous superciliary arch, and very prognathous).

Outside Australia, Huxley claimed to have found the Australioid type in the interior of the Deccan, and among the Egyptians. The standard for the Negroid type is the African negro. Huxley wrongly considered this type as almost without exception dolichocephalic. It generally lacks a bony superciliary arch; skin and eyes are brown to black; the hair black, short and frizzly or wooly; lithe nose flat and broad; the lips thick and protruding, while prognathism is universal. According to Huxley, the particular modifications of the Negroid type are: the small Bushmen with lighter skin; the partly brachycephalic Negritos with heavy superciliary arch, living in southern and south-eastern Asia (the Malay Peninsula), and in the Andaman, Philippine, and South Sea Islands (Papuans) as far as Tasmania. Among these Negritos there has been a considerable crossing with Polynesians and Malayans.

Huxley grouped together the inhabitants of the greater part of Central Europe as the Xanthoeroi or fair-white type. This group is characterized by an almost colourless soft skin, blue or grey eyes, and light hair; the shape of the skull ranges from dolichocephalic to brachycephalic. In the south and west this type comes into contact with the Melanochroi; in the north and east, where it extends to Hindustan, with the Mongoloid type.

According to Huxley all Asia and its surrounding islands in the east and south-east, the east and north- east of Europe and the whole of America are inhabited by the Mongoloid type (yellowish-brown skin, black eyes, black, lank hair, small, flat nose, oblique fold of the eyelid, but no projecting bony superciliary arch); the type is partly brachycephalic, partly dolichocephalic. The Melanochroi or brunettes live around the Mediterranean Sea, and extend through Asia Minor across Arabia and Persia to Hindustan. The skin is brownish, the fine wavy hair almost black, the eyes dark. Huxley considered the Melanochroi the result of a mixture of the Xanthoeroi and Australioids.

From these three main races (called archimorphic by C.H. Stratz), G. Fritsch has distinguished the mixed races derived from them as metamorphic. Both divisions have a strongly developed instinct for migration (nomadic peoples), which has promoted the growth of civilization. At the same time Fritsch and Stratz assumed a series of tribes without an instinct for migration (non-nomadic peoples); these were named by Stratz protomorphic. These theories, however, have scientific value as working hypotheses, even though the one or the other may prove to be incorrect.

Stratz has selected the following as the criteria for the three archimorphic races. Those of the melanodermic or black race are: excessive length of the legs; total height 7 to 7.5 heads; skin from dark brown almost to black; the hair of the head thick, black, and frizzly, with an elliptical cross-section; hair on the body scant; an inclination to dolichocephaly (with a very decided breadth of the skull behind); pronounced prognathism; powerful broad, and high jaws.