All mammals, including human beings, have seven neck vertebrae but eight neck nerves. In all of them, the first two vertebrae (atlas and axis) are built so as to allow nodding (i.e. fore and aft) or flexion and extension movements of the skull on the atlas; and rotational (i.e. left and right swinging) movements of the skull and atlas upon the axis, in which the rest of the neck vertebrae participate to a lesser extent. Raymond Dart An Anatomist's Tribute to F.M. Alexander |