Relationships between the vertebral parameters C2--C6 during movement of the cervical "vertebral units" in the sagittal plane.

In the paper it is endeavoured to set up objective criteria for the detection of a qualitatively abnormal mobility of the cervical vertebral units. Three scalar parameters were chosed to characterize the position of a cervical vertebra in the sagittal plane. By the aid of the parameters, graphs were drawn illustrating the reciprocal functional dependence of the vertebral parameters. It is stated that a discontinuous variation of the angle between the straight lines shown in the Fig. 4 and 8 and the axis of abscissae can be taken as an objective criterion of a qualitatively abnormal movement of the cervical vertebral units.