The purpose of this study was to develop new standards for determining the sex of fragmentary human skeletal remains. We measured height, width, and length of the mastoid process in medieval to early modern Japanese skeletons, from the Yuigahama-minami and Hitotsubashi sites, in order to provide a metric standard for the diagnosis of sex using the mastoid process. We calculated discriminant functions based on these measurements; the accuracy of sex classification was over 80% using a single variable, and reached 82-92% with two variables, mastoid height and width. This accuracy is equal to or better than that reported by some previous studies of sex determination using the cranium. However, when we examined intra-and interobserver errors in the mastoid process measurements, we found a high level of errors, and this highlights the difficulty involved in intraobserver repeatability and interobserver reproducibility. Our results imply that, in order to achieve reliable results of sex determination using the mastoid process, the measurement methods need to be carefully determined and executed.

This study measured the medieval crania from the Kanto District in Japan and compared the measurements with those of the preceding studies for the purpose of clarifying the morphological variation within several medieval populations in the Kanto District and between populations from the Kanto and northern Kyushu-Yamaguchi Districts. The materials utilized in this study consist of human skeletal remains from the Yuigahama-minami (individual burials), Chusei-Shudan-Bochi, Gokurakuji sites in the Kamakura city, the Kanto

平成 17 年 5 月 2 日受付，平成 18 年 4 月 14 日受理 ) 要 約 本研究は頭蓋の X 線 CT(Computed Tomography)画像から上顎洞の形態やサイズを計測し，分析を行 なったものである。近代日本人女性乾燥頭蓋 42 体 84 側(平均年齢 38.9 歳)を資料として，CT 装置による 撮影を行ない，得られた画像から画像解析ソフトによる上顎洞の前後径，高径，幅径，体積の計測を行な い，本研究と同様の機器・手法で行われた同時代の日本人男性乾燥頭蓋に関する計測結果(野木・金澤， 2001; 野木，2002)との比較を行なったところ，前後径，高径，体積の各項目において，男性の上顎洞よ りも女性の上顎洞のほうがサイズは小さかった。主成分分析を行ったところ，上顎洞の大きさの変異は第 1 主成分のサイズファクターで説明されることがわかった。頭蓋の直接計測値との相関については，体積 が顔長，頭蓋最大幅，上顔高との正の有意な相関があり，前後径と頭蓋最大長，高径と顔長に有意の相関 がみられた。上顎洞底部の形態を大きく 3 つのタイプ， 「ラウンド型」 「フラット型」 「イレギュラー型」に 分類したところ，ラウンド型は他のタイプと比較して全体の体積が小さく，イレギュラー型は大きかった。 年齢や歯の残存状態と上顎洞のサイズとの関係をみていくと，20 歳代，完全歯列の上顎洞はサイズが最大 で，50 歳以上，無歯顎へと移行していくにしたがってサイズは減少していった。 キーワード：上顎洞，近代日本人，CT，性差 AbstractThis study was carried to investigate the morphometry of the maxillary sinus and the three dimensional relationship between the maxilla and the maxillary sinus with the use of Computed Tomography (CT) images. Materials used were dry skulls of 42 modern Japanese female skulls (average age of 38.9) housed in the University Museum of the University of Tokyo. CT scanning images of the maxillary sinus were measured by calibrated software program, CT Rugle. The length, width, height, and volume of the sinus were measured. It was *日本大学松戸歯学部解剖人類形態学講座 〒 271-8587 千葉県松戸市栄町西 2-870-1

High frequency of the bony deposition and the bony absorption observed inside of maxillary sinus indicated the prevalence of the maxillary sinusitis. It is pointed out that the inflammation frequency of maxillary sinusitis has the close relationship with a living environment. However, there were few studies on the epidemic study of maxillary sinusitis for a historical Japanese group. Skulls excavated from the medieval group cemetery in Kamakura Yuigahama, Japan were used. It was suitable for observation of the wall of the maxillary sinus that most of their facial bones were partly damaged. The number of skull were 592, and totally 809 maxillae were macroscopically observed under the electric light. Inner surfaces examined were superior, buccal, basal, anterior and posterior walls. The lesions were classified into seven categories such as pits, opening, spicule, bridge,

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