Abstract: The materials studied in this paper include 115 male and 54 female innominate bones of adult si^e, most of which are stored in the Department of Systematic Anatomy of Xinjiang Medial College. They were unearthed from the vicinity of Uromuchi. Most of the specimens were sexed on the basis of the pelvis morphology by the authors, a few female specimens were sexed based on the typical morphology shown on the innominate bones only. No pathological bones are included in this study. All specimens belong to adult individuals.
The measurements included in this paper are defined as follows:
Pubic length I. Distance from the central point of acetabulum to the upper border of the pubic symphysis.
Pubic length II. Minimum distance between acetabulum and upper border of pubic symphysis.
Ischium length I. Maximum distance between the central point of acetabulum and the ischial tuberosity.
Ischium length II. Maximum distance between the upper border of acetabulum and the lower border of ischial tuberosity.
Diameter of acetabulum. Maximum vertical diameter of it.
Breadth of sciatic notch. Distance between posterior inferior iliac spine and spine of ischium.
Depth of sciatic notch. Length of a vertical line from the deepest point of this notch to its breadth.
OB. Measured as shown in Fig. 1.
The data of measurements and indices are listed in Table 1 in which the items are arranged from above downward as follows: pubic length I, ischium length I, ischiumpubis index I, pubis length II, ischium length II, ischium-pubis index II, diameter of acetabulum, diameter of acetabulum X 100/pubis length II, breadth of sciatic notch, depth of sciatic notch, index of sciatic notch, OB, OB X 100/breadth o￡ sciatic notch. In this table, ++ and + stand for statistically very significant (T>3) and significant (3〉T〉2) sexual differences respectively.
Figures 3—10 show the distribution by sex of various items of measurements or indices. One can diagnose modern Han innominate bones of unknown sex with reference to these features. The ischium-pubis index by itself gives the best sorting.
We calculated the average of means of each item of both sexes and used it as the boundary value of each item. If all those specimens with larger (or smaller) value are diagnosed as belonging to the same sex, we are making wrong sorting for some specimens. The percentages of wrong sorting by using different items are listed in Table 2.
Another attempt we made to get better result of sorting is to plot the values of one item against those of another item on a graph paper to obtain s series of diagrams of sex distribution (Figures 11一17) which are very useful for diagnosing innominate bones of unknown sex.
Data of various ethnic groups published by other authors are compared with the data of the present authors (Table 3). Chinese Han innominate bones are nearer to those of American Whites and Eskimos than to those of Negros and Australian Aborigines. In Table 3, ++ and + stand for very significant and significant statistical differences respectively.

Key words: Innominate bone; Sex difference; Sex diagnosis; Han nationality