Table 2.

Heights of the spinal canal and cord measured on transverse images and ratio of the height of the spinal cord to the canal.

Level	Canal (mm)	Cord (mm)	Cord-to-canal ratio
C1–C2	8.49 ± 1.07	5.54 ± 0.68	0.67 ± 0.07
C2	9.56 ± 1.49	5.74 ± 0.78	0.61 ± 0.05
C2–C3	7.06 ± 1.09	5.03 ± 0.78	0.71 ± 0.04
C3	7.39 ± 0.91	5.42 ± 0.82	0.73 ± 0.04
C3–C4	6.75 ± 0.92	5.10 ± 0.71	0.76 ± 0.03
C4	7.40 ± 0.87	5.55 ± 0.80	0.75 ± 0.03
C4–C5	7.10 ± 0.85	5.55 ± 0.73	0.78 ± 0.03
C5	7.97 ± 0.94	6.06 ± 0.84	0.76 ± 0.03
C5–C6	8.11 ± 0.98	6.26 ± 0.83	0.77 ± 0.03
C6	8.68 ± 1.01	6.54 ± 0.84	0.75 ± 0.03
C6–C7	8.25 ± 0.98	6.34 ± 0.84	0.77 ± 0.03
C7	8.03 ± 0.91	6.00 ± 0.75	0.75 ± 0.04

Data are expressed as the mean ± standard deviation. Abbreviations are the same as those in Table 1.