Table 1 : Measures of Antero-Posterior Diameters (APD1) of the lumbar spinal canal and the lumbar dural sac (APD2), and the ratio of
the APD2 on the APD1.

	LUMBAR CANAL (APD1)		DURAL SAC (APD2)		RAPPORT (R1)
	Min - Max	Moyenne	Min - Max	Moyenne	Min – Max	Moyenne
L1	11.9 - 26.1	16.05±1.84	10 - 14.5	12.77±1.4	0.74 - 0.96	0.85±0.07
L2	10.4 - 20	15.26±1.72	11.2 -13.5	12.4±0.63	0.77 - 0.88	0.84±0.03
L3	10 - 25.1	14.51±1.97	11 -13	11.06±1.02	0.68 - 0.95	0.81±0.07
L4	10.1 - 23.5	15.09±2.34	09 -13	10.7±1.32	0.58 - 0.96	0.76±0.09
L5	10 - 30.3	16.16±2.98	9.5 -13	11.38±1.34	0.67 - 0.85	0.76±0.06
Moyenne générale	10.48±0.5 -25.00±2.6	15.41±0.55	10.7±1,49 -12.77±0.6	11.66±0.66	0.76±0.66  -0.85±0.66	0.80±0.04