Table 4.

The spinal cord occupation rate of dural sac in cross-sectional area on each position.

Level	CSM patients		Asymptomatic subjects
	Flexion (%)	Extension (%)	Neutral on MRI (%)
C2/C3	40.7 ± 5.7	38.4 ± 5.3	37.4 ± 6.8
C3/C4	46.6 ± 6.2	45.3 ± 6.2	45.1 ± 8.0
C4/C5	45.1 ± 6.2	46.3 ± 7.0	47.0 ± 8.7
C5/C6	43.9 ± 6.9	45.3 ± 6.5	46.7 ± 8.4
C6/C7	39.8 ± 6.3	42.0 ± 6.7	41.8 ± 8.5
C7/T1	36.0 ± 7.6	36.3 ± 6.5	33.5 ± 6.6

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

CSM indicates cervical spondylotic myelopathy.