Table 2.

The mean values of the intervertebral translations with 95% confidence intervals at each spinal level during cervical flexion and extension

Level		Mean (mm)	Standard deviation	Individual 95% confidence interval		Comparison between flexion and extension P value
				Lower bound	Upper bound
C2/3 Translation (1)	Anterior	0.7	0.2	0.6	0.8	0.543
	Posterior	0.7	0.2	0.6	0.8
	Total translation	1.4	0.3	1.3	1.6
C3/4 Translation (2)	Anterior	1.0	0.3	0.9	1.1	0.037†
	Posterior	1.1	0.3	1.0	1.2
	Total translation	2.1	0.5	1.8	2.3
C4/5 Translation (3)	Anterior	1.2	0.3	1.1	1.4	0.039†
	Posterior	1.3	0.4	1.1	1.4
	Total translation	2.5	0.6	2.2	2.8
C5/6 Translation (4)	Anterior	1.1	0.3	1.0	1.2	0.005†
	Posterior	1.1	0.4	1.0	1.3
	Total translation	2.2	0.6	2.0	2.5
C6/7 Translation (5)	Anterior	0.9	0.4	0.7	1.1	0.001†
	Posterior	0.4	0.7	0.1	0.7
	Total translation	1.3	1.0	0.8	1.7
Comparison among 5 spinal levels  P value	Anterior translation	<0.001* (1,2)(1,3)(1,4)(3,5)
	Posterior translation	<0.001* (1,3)(1,4)(2,5)(3,5)(4,5)
	Total translation	<0.001* (1,2)(1,3)(1,4)(2,5)(3,5)(4,5)

^* P < 0.05 compared among spinal levels; There were significant differences between C2/3 & C3/4 (1,2), C2/3 & C4/5 (1,3), C2/3 & C5/6 (1,4), C3/4 & C6/7 (2,5), C4/5 & C6/7 (3,5), and C5/6 & C6/7 (4,5) in total translation during cervical motion

^†P < 0.05 compared between flexion and extension within each level; There were significant differences between anterior and posterior translation within C3/4, C4/5, C5/6 and C6/7 levels during cervical flexion and extension