John Cleland

“ It appears, therefore, that the transverse ligaments of the atlas and other vertebræ in birds, and the ligamentum conjugale costarum, and transverse ligament of the atlas in mammals, are all homologous structures: and, in that case, the only difference between the atlo-occipital articulation in the mammal and in the bird is, that while in the latter it is single, in the former it is divided into two lateral parts. But this is not an important distinction; for in the atlo-axoid articulation, we find the arrangement in many mammals, as in the human subject, similar to that of the atlo-occipital ”

“ When, in the human subject, a process of bone passes up from the arch of the atlas, to meet the superior articular surface and convert the groove for the nerve and vertebral artery into a foramen, the process in question is a true oblique process. ”

“ If, in addition, we were to imagine the tip of the transverse process thickened and projecting upwards to meet the superior articular surface, we should then have presented to us the condition of parts found in the pig and the sheep. ”