Second cervical vertebra, or epistropheus, from above. Second cervical vertebra, epistropheus, or axis, from the side. Seventh cervical vertebra. 脊柱 Posterior
下数的第二块脊椎,由寰枢关节将C1(寰椎)和C2连起。 枢椎最显著的特征是其被称作齿突(dens)的结构,自椎体上面垂直发出,因此枢椎也被称为vertebra dentata。在部分绞刑中,齿突骨折并伤到延髓,从而导致犯人死亡。 Netter, Frank. Atlas of Human Anatomy
Batman! (页面存档备份,存于互联网档案馆) and More on Qiaowanlong already (页面存档备份,存于互联网档案馆), blog posts at Sauropod Vertebra Picture of the Week concerning Qiaowanlong
極龍屬於主龍形類。其他的研究人員則提出北極龍屬於三稜龍目。 Adams, A. L., (1875) On a fossil saurian vertebra, Arctosaurus osborni/Arctic region. Proceedings of the Irish Academy 2:177-179