comb. form of ATLAS sb.1 (in the physiological sense), as in atlanto-axial, etc.
1839. Todd, Cycl. Anat. & Phys., III. 457/1. The atlanto-occipital articulation.
1881. Mivart, Cat, 55. The ventral atlanto-axial ligament connects the ventral arch of the atlas with the centrum of the axis.