Correlation between interorbital widthfacial height index and nasal widthfacial height index. Craniometric studies. No. 32код для вставкиСкачать
CORRELATION BETWEEN INTERORBITAL WIDTH/ FACIAL HEIGHT INDEX AND NASAL WIDTH/ FACIAL HEIGHT INDEX CRANIOMETRIC STUDIES, No. 32 The favorable correlation shown by the author(1) to exist between the nasal width and the interorbital width stimulated him to investigate the possible existence of a correlation between two cranial indices in which these two cranial dimensions participate. These indices are the interorbital width/facial height index, described in Craniometric Study no. 30, and another new cranial index recently described by him, namely, the nasal width/facial height index(2). It may be mentioned at the very outset that such a correlation not only existed, but was also found to be of a highly favorable nature in all the racial types of modern man that were available for study. As the nasal width/facial height index has only recently been devised by the author, its ranges of variation, standard deviations, and coefficients of variability have yet to be recorded in the case of the Hamann Museum white and negro crania. He had previously noted(2) that the ranges of variation of this index in the Eskimo crania varied from a maximum of 37.6 to a minimum of 25.9, the actual range being thus 11.7. This was slightly greater than the range exhibited by the interorbital width/facial height index, but definitely less than the range shown by the nasal index in this racial group. However, it was decidedly less than the ranges for the nasal width/facial height index in the case of the Hamann Museum white and negro crania (table 1). One would naturally expect to find a comparatively small range of variation in a homogeneous racial type like the Eskimo, and a relatively extensive range in heterogeneous racial groups, as 248 249 CRANIOMETRIC STUDIES represented by the Hamann Museum white and negro crania. The writer found the ranges to be rather extensive in the latter crania. These results are recorded in table 1. TABLE I The nasal width/facial height index displays the usual wide ranges of variation, except in a comparatively homogeneous race like the Eskimo Male white (Hamann Museum), Male negro (Hamann Museum), Male Eskimo (U.S. National Museum), Mazimum Minimum Range 42.1 46.4 37.6 28.1 28.9 25.9 14.0 17.5 11.7 The writer calculated the standard deviations and coefficients of variability of the nasal width/facial height index for the Hamann Museum white and negro crania and f o r the Greenland Eskimo male crania (U. S. National Museum). These are shown, together with their probable errors, in table 2. It will be noticed that the standard deviations, like the ranges of variation, are lower in the Eskimo than in the white and negro crania. TABLE 2 The standard deviations of the nusal width/facial height index are higher in the Hamann Museum white and negro crania than in a comparatively homogeneous race like the Eskimo S.D. Male white (Hamann Museum), 3.14 2 0.1933 3.86 k 0.2376 Male negro (Hamann Museum), Male Eskimo (U.S. National Museum), 2.86 2 0.2491 c. of v. 9.208 2 0.5669 10.48 & 0.6452 9.22 k 0.80306 The writer has shown in Craniometric Study no. 30 that these Greenland Eskimo male crania exhibited the lowest average interorbital width/facial height index among all the racial types of modern man that were available for study, the actual figure being 29.3 (+ 0.3514). He was therefore much interested to note that the same racial group possessed also the lowest average for the nasal width/facial height index, namely, 31.0 (k 0.3263). As a possible contrast to these low averages, the writer decided to make a comparison of the same two indices in the Hamann Museum male negro crania. This racial group presented an average interorbital width/ facial height index of 38.2 (+0.3396), and a n average nasal 250 J O H N CAMEROX width/facial height index of 38.3 ( -L 0.3361). It was evident that these results indicated a marked increase when compared with the corresponding indices for the Eskimo. By the way, it was interesting to note that the averages for these two indices in the Eskimo were very near to one another (29.3 and 31.0), while in the negro crania they almost exactly corresponded (38.2 and 38.3). The writer was thus enabled to discover two racial groups placed at the extreme ends of the scale, so far a s their interorbital width/facial height and nasal width/facial height indices were concerned, the Greenland Eskimo crania being at the bottom of the scale and the negro crania at the other end. His next duty manifestly was to ascertain the position occupied in this scale by the corresponding indices for the Hamann Museum white crania. As a result he found that the average interorbital width/facial height index for these white crania was recorded as 36.01 (+ 0.3396). That is to say, it occupied a position more or less intermediate between those for the Eskimo and negro crania. I n order to prove the existence of any definite degree of correlation, the average nasal width/facial height index f o r these white crania would likewise have to occupy a similar intermediate position. As a matter of fact, it did, for it was calculated to be 34.8 (t0.2734), a result which was of course higher than the corresponding index in the Eskimo and lower than that found in the negro. These results, it may be added, were confirmed by the Hamann Museum white and negro female crania. These data are all recorded in table 3, in which it will be noted how close the averages f o r these two indices are t o each other in all the racial groups. I t will be further observed that the average nasal width/facial height index is slightly higher than the average interorbital width/facial height index in each racial type, with the exception of the white crania. Attention may again be directed to the position in table 3 occupied by the white crania, that is, intermediate between the Eskimo and negro crania. 251 CRAXIOMETRIC S T U D I E S TABLE 3 A correlation was found to exist between the interorbital width/facial height index and t h e nasal width/facial height index in the various racial types that were available for study. T h a t is t o say, a low average interorbital width/ facial height indez was usually associated with a low nasal width/facial height index, and vice versa Interorbital w i d t h / f a c i n l height index Male Eskimo (U. S. National Museum), Male white (Hamann Museum), Female white (Hamann Museum), Male negro (Hamann Museum), Female negro (I-Iamann Museum), 49.3 36.01 35.5 38.2 38.6 .%-ma1w i d t h / f a c i a l height i n d r z 31.0 34.8 35.2 38.3 39.2 I n view of the results that have just been recorded in table 3, the author felt encouraged to undertake the manifestly complicated mathematical calculations that a r e necessary in order to ascertain the exact degree of correlation existing between these two cranial indices. He therefore selected the Hamann Museum white and negro crania and the Greenland Eskimo crania for the necessary calculations. As a matter of fact, the correlations could not have been calculated in the case of the other racial groups, on account of the small numbers of crania represented. The coefficient of correlation in the case of the Hamann Museum male white crania was found to be 0.6583, a result which indicated, of course, a highly favorable degree of correlation. The probable error of this coefficient of correlation was calculated to be -I- 0.04934. The result yielded by the Hamann Museum male negroes was not quite so good, the coefficient f or this cranial group being 0.5685, with a probable error of r+ 0.05894. The writer expected to obtain a highly favorable coefficient of correlation in the case of the Eskimo crania, which one would naturally look for in a comparatively homogeneous race. Their coefficient of correlation was, however, only +0.4212, with a probable error of t 0.1014. This low degree of correlation was, of course, explained t o some extent by the small numbers of Greenland Eskimo crania that were available, namely, thirty-that is to say, exactly one-half of the numbers examined in the other two racial groups. I n calculating the coefficient of correla- + + 252 J O H N CAMERON tion f o r these Eskimo crania, the total yielded by the + s y column was only 131.50, while the total f o r the -sy column amounted to 34.25. This meant., of course, a very narrow margin of difference f o r the production of a really favorable correlation. CONCLUSIONS 1. The author found that a favorable correlation existed between the interorbital width/facial height index and the nasal width/facial height index in several racial types representative of modern man. That is to say, a high interorbital width/ facial height index was associated with a high nasal width/ facial height index, and vice versa. 2. Among the racial types that were available, the coefficient of correlation was found to be 0.6583 for the Hamann 0.5685 for the male negro Museum male white crania, crania, and 0.4212 for the Greenland Eskimo male crania of the U. S. National Museum. 3. The author hopes that at some future date, the correlations between these two cranial indices will be investigated by craniologists in other racial groups, as these become available f o r study. + + + LITERATURE CITED 1 CAMERON,JOHN 1931 Correlation between the interorbital width and the nasal width of the skull. Amer. J. Phgs. Anthrop., XV. 2 1929 The proportion between the nasion-alveolar height and the nasal width: A new cranial index, and its significance. Jour. Anat., LXIII.