The Lateral Movement in the Atlanto-Axial Joints and its Clinical Significance

The principal movement possible to the atlanto-axial joints is indubitably that made by the dens epistrophei round a vertical axis, one thus whereby the atlas and, a t the same time the head, makes a rotatory motion.Few researchers have turned their attention to the question as to whether the atlas, in relation t o the epistropheus, may also move ro iind the other theoretically conceivable axes, viz. the transverse arid the sagittal axes, whereby, thus, there would be ante-and retro-flexion, and abduction of atlas and head respectively.R. FICK (1911), in his well-known work on arthrology, says regarding these movements in the lower cranio-vertebral joint (p. 120):