犬の下顎骨の比較形態学的研究
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概要
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Measurements were taken of the length and width of the head with use of dog skulls of Western, Japanese, and Mixed Breed preserved in the First Department of Oral Anatomy, and the ratios of the two, or cephalic indexes were determined. Classifications based on the indexes were obtained in three types : dolichocephaiic type, mesocephalic type, and brachycephalic type. For the present study, the mandibles were examined of 30 cases of Western Breed, 16 cases of Japanese Breed, and 24 cases of Mixed Breed in mesocephalic type. This examination was made with instruments and macroscopically to determine and analyze the difference in size and morphology. The results were as follows. 1. All mandibles have 3 pairs of mental foramens. Among the three, the middle foramen was biggest. The position of the middle mental foramen between p_1 and p_2 was most frequent for 3 Breeds and accounted for about 40%. The most frequent opening direction of the middle mental foramen was 'ahead' in 3 Breeds. The diameter and position of mental foramen were no different in 3 Breeds. 2. By the diameter of mandibular foramen, Japanese Breed is biggest, but the position was no different in 3 Breeds. 3. By the measurements of mandible, Japanese Breed showed greater values than the other 2 Breeds in all items except 'Angle of right and left body of mandible'. 4. According to indexes concerned with mandible, Western Breed showed deeper incision at mandibular notch, slenderer at process of jaw angle, and the overall shape of the mandible is slenderer than the other 2 Breeds. 5. In comparison of coefficient of correlation among 3 items, or length, height, and width of mandible, 3 Breeds showed a much positive correlation, but there is no correlation between these 3 items and angle of mandible. 6. For macroscopic observation, the degree of growth, for 3 Breeds, was examined of 6 items. As a result, there is no difference between Western Breed and Mixed Breed. Japanese Breed seemed to have developed better than the other 2 Breeds in 3 items, that is, pterygoid fossa, masseteric fossa, and mental spine.
- 九州歯科学会の論文
- 1982-12-25