Table 2. Distribution of cross sectional area of dura (mm²).

Men	Total	<50	50–59	60–69	70–79	≧80	Standardized Test Statistic	p-value
L1/2	172[149–192]	192[174–212]	177[154–193]	170[147–189]	154[132–181]	157[147–186]	-4.619	<0.0005
L2/3	146[120–172]	176[151–187]	157[136–174]	143[117–163]	126[107–158]	142[109–165]	-5.246	<0.0005
L3/4	132[102–165]	164 [146–181]	144[122–178]	122[102–149]	114[86–140]	119[88–137]	-5.652	<0.0005
L4/5	129[91–168]	166 [128–198]	140[111–186]	120 [88–157]	113[90–146]	99[73–154]	-5.538	<0.0005
Women	Total	<50	50–59	60–69	70–79	≧80	Standardized Test Statistic	p-value
L1/2	177[157–202]	204[176–220]	186[165–205]	176[156–199]	165[147–189]	168[145–191]	-7.506	<0.0005
L2/3	158[133–184]	188[168–210]	170[147–190]	153[130–178]	145[123–169]	148[112–161]	-8.915	<0.0005
L3/4	139[109–174]	179[149–197]	154[126–177]	134[107–163]	126[97–163]	113[73–153]	-8.775	<0.0005
L4/5	127[96–166]	149[111–189]	140[109–166]	123[96–157]	112[83–160]	107[77–141]	-6.003	<0.0005

Values are the median [first quartile- third quartile].

The CSAs had a tendency to decrease with age and lower intervertebral levels in both genders (Jonckheere-Terpestra test; p< 0.0005).