Effect of Initial Head Position on Range of Active Cervical Flexion

[Purpose] The aim of this study was to compare the segmental and total ranges of cervical flexion with two different starting positions: flexion from a neutral position (Flexion) and flexion from a position of forward inclination of the upper cervical spine (Finc-Flex). [Subjects and Method] Ten healthy volunteers (10 men, 26–43 years of age) were recruited. The consenting volunteers were referred for radiographs. Three lateral radiographs were taken in a neutral position, Flexion, and Finc-Flex. Differences in segmental and total sagittal rotation angles between Flexion and Finc-Flex were analyzed. Within-group differences were assessed using the paired t-test. [Results] A significant difference was noted in the segmental range of flexion at C0/C1 and C2/C3, but there was no difference in the total range of flexion. Segmental ranges of flexion at C0/C1 (-3.10) and C2/C3 (4.80) in Finc-Flex were significantly greater than at C0/1 (-4.70) and C2/3 (2.90) in Flexion. [Conclusion] The two different starting positions of the head in flexion influenced the segmental range of flexion at C0/C1 and C2/C3 in different ways. The results of this study do not support the belief that cervical flexion starting from a position of forward inclination in the upper cervical spine actively restricts total cervical range of flexion.