It simply means the question has not been systematically studied
While previous in vivo studies investigating cervical segmental ranges of motion did not perform statistical analysis on potential effects of the segmental level, the numbers reported in these studies also suggest a considerably lower range of motion of the C2C3 motion segment compared to the lower cervical motion segments in flexion/extension 10,15,16 , confirming the findings of the present in vitro study
These might act peripherally (i.e., bile duct ligation), centrally (i.e., huge intraventricular hemorrhage), and then peripherally and centrally, and centrally and peripherally, along with the three interconnected body cavities, as specifically shown in the maintained intra-abdominal hypertension studies [22], as the disturbances may be rapidly transmitted from the periphery to centrally, and from centrally to the periphery, through the venous system
doi: 10.1016/j.fertnstert.2011.07.928 226 FlorouPAnagnostisPTheocharisPChourdakisMGoulisDG
Malmgren, S