Table 2.

The spinal cord occupation rate of dural sac in anteroposterior diameter on each position.

Level	CSM patients		Asymptomatic subjects
	Flexion (%)	Extension (%)	Neutral on MRI (%)
C2/C3	62.2 ± 7.1	60.8 ± 7.2	62.3 ± 7.7
C3/C4	64.5 ± 6.7	61.0 ± 9.6	65.8 ± 8.8
C4/C5	60.0 ± 8.5	58.0 ± 9.9	64.7 ± 9.2
C5/C6	57.2 ± 8.4	58.6 ± 9.8	64.6 ± 8.9
C6/C7	55.8 ± 6.2	61.5 ± 11.3	61.1 ± 9.1
C7/T1	51.0 ± 6.4	52.0 ± 9.1	53.7 ± 7.8

Values given are mean ± standard deviation (SD) unless otherwise specified.

CSM indicates cervical spondylotic myelopathy.