资阳人头骨化石,是新中国成立后首次发现的保存较为完整的人类化石,曾经引起学术界的广泛关注。由于其出土的具体位点和层位不是很清楚,对其年代目前还存有争议。长期以来,对资阳人的研究局限于传统的头骨外部形态的描述和测量。本文利用高分辨率工业CT（Computed tomography）扫描资阳人头骨,并对其内部解剖结构 (包括骨壁结构、额窦、骨内耳迷路、颞骨乳突小房、颅内模) 进行3D虚拟复原和研究,以期获得更多的形态信息。CT断层图显示资阳人头骨的骨壁板障层较厚,远大于外板层和内板层,支持以往研究认为的该头骨属于50岁以上个体的鉴定结果。额窦呈叶形,局限于两侧眼眶的内上方;左、右侧额窦的表面积分别为1780mm²和2910mm²。骨性内耳迷路半规管的大小及其比例,与尼安德特人不同,而位于晚更新世和全新世现代人变异范围之间。颞骨乳突小房为气化型,几乎占据了整个乳突部。根据复原的颅内模,资阳人的颅容量约为1250mL。颅内模的各项测量数值虽然都偏小,但脑的绝大多数形态特征、宽-高指数、顶叶-脑长指数都位于现代人的变异范围之内,而与直立人和更新世古老型人类不同。资阳人头骨内部解剖结构保留有少量原始特征,包括枕叶向后突显著、大脑窝比小脑窝大而深,这些特征不同于全新世人类,更类似于晚更新世早期现代人。

Although the specific location is not clear and its dating is still debated, the Ziyang human fossil has attracted extensive attention from academic circles because it is the first almost complete human skull fossil found after the establishment of the People’s Republic of China. For a long time, the research on the Ziyang skull was limited to only external morphology and measurements using traditional methods. In order to better understand the evolutionary stage of the Ziyang hominid, a high-resolution industrial CT scanner was used to analyze its internal anatomy, and 3D virtual reconstructions of its bone structure, frontal sinus, bony labyrinth, pneumatization of mastoid air cells, and endocast were created and analyzed. CT images of the bone structure shows that the diploë is very thick—much thicker than the outer and inner layers. This supports the previous identification results of the Ziyang individual over 50 years old. The frontal sinus of the Ziyang is in the shape of a leaf, bilaterally located on the inner and upper orbital areas, with surface areas on the left and right of 1780 mm²and 2910mm², respectively. The size and proportion of the Ziyang semicircular canals of the bony labyrinth are different from Neandertals, but are in the ranges of those from Late Pleistocene Homo sapiens and recent modern humans. The pneumatization of mastoid cells was in pneumatic type, and almost occupied the entire mastoid process with pneumatic cavities. Based on the 3D virtual reconstruction of the endocast, the cranial capacity of the Ziyang skull was estimated at around 1250 mL. Although the endocast is small in all measurements, most of the brain morphology as well as the width-height index and the parietal lobe-length index were all within the variation range of modern humans, which are different from those of Homo erectus and Pleistocene archaic humans. The internal anatomy of the Ziyang skull retains a few original features, including the two occipital lobes that are prominently backwardly convex, and the cerebral fossa, which is larger and deeper than the cerebellar fossa. These two features are different from Holocene humans but are similar to Pleistocene early modern humans.