Abstract:

There may be three kinds of bone bridges on the vertebral artery sulcus of Macaca mulatta in Taihang Mountains, which are ventral bridge, lateral bridge and dorsal bridge. This paper explores their distribution characteristics. It is helpful for us to speculate on evolutionary trends in primates. It also has important clinical significance for people to understand the variations observed in the human atlas. It focuses on observing those non-measured and measured characteristics of the atlas bridge of Macaca mulatta in Taihang Mountains, and count its lateral differences, gender differences and population differences. Based on such research significance and research focus, this paper selects a total of 57 specimens (adult bone specimens) (male 17, female 40) of the atlas bridge of Macaca mulatta. For each atlas specimen, the width of three possible atlas bridges located on the vertebral artery sulcus is measured and analyzed. Firstly, observe and describe its morphology, and accurately observe and count the bridge widths of the atlas ventral bridge, lateral bridge and dorsal bridge; Then, SPSS statistical software was used to process the previously obtained measurement data and observe the occurrence rate, morphological characteristics, and combination types of the atlas bridge; Finally, further explore the possible influencing factors that may occur during the evolutionary process of the atlas bridge in primates. The statistical results show that the variability of the atlas bridge in macaques is significantly different (P<0.05), and the ventral and dorsal bridges are constant (100%), while the lateral bridges are basically constant. However, there are also some missing cases (90.3%), indicating that the ventral and dorsal bridges are stable characteristics of Macaca mulatta; The main type of atlas bridge in Macaca mulatta is the primitive type A, which is separated from the main type D of human animals. Based on the above characteristics, we conclude that the three atlas bridges of macaques are a stable trait with a significantly higher incidence than those of apes. In addition, this article categorizes the atlas bridge types of primates, which can provide reference suggestions for researchers to speculate on the corresponding population evolution degree.

Key words: Atlas, Bone bridge, Macaca mulatta, Primates