Table 6. Group comparison of disc herniation segments.

Segment, n (%)	PI	PT	SS	TK	LL	Height of anterior margins	Height of posterior margins	height of middle margins	Height difference between anterior and posterior margins	Left FJA	Right FJA	Bilateral angle difference
L4/5, 63 (50.0)	48.98±9.924	20.82±8.376	28.18±10.189	22.46±9.471	35.59±18.120	9.00±2.386	6.29±1.755	8.26±1.779	2.71±2.386	42.82±11.089	43.26±9.226	6.59±5.662
L5/S1, 59 (46.83)	43.86±7.917	16.01±7.470	27.88±9.641	21.18±10.367	33.23±19.193	10.13±2.644	6.20±1.511	8.16±1.739	3.92±2.512	47.34±9.605	47.91±13.613	9.88±8.140
t value	3.132	3.344	0.168	0.715	0.697	−2.483	0.282	0.309	−2.739	−2.402	−2.223	−2.582
P value	0.002	0.001	0.867	0.476	0.487	0.014	0.779	0.758	0.007	0.018	0.028	0.011

Data are presented as mean ± standard deviation. Independent sample t-test, P<0.05. SS, sacral slope; PI, pelvic incidence; PT, pelvic tilt; TK, thoracic kyphosis; LL, lumbar lordosis; FJA, facet joint angle.