Table 3.

Polynomial coefficients (C₁, C₂, C₃ and C₄) for prediction equations of 20 articular facet joint parameters per vertebral level of the human lumbar spine. Refer to Fig. 1 for abbreviations.

Parameter	Abbreviation	C1	C2	C3	C4	SE	R2	P-value
Facet dimensions
Height	FHSL	−4.775	4.188	−0.309	0.007	1.18	0.647	0.0046
	FHSR	33.916	−2.519	0.068	0.001	0.87	0.751	0.0006
	FHIL	62.954	−6.484	0.235	−0.002	0.68	0.910	1.49E-06
	FHIR	82.879	−10.102	0.444	−0.006	0.64	0.924	5.62E-07
Width	FWSL	240.180	−35.123	1.759	−0.029	1.49	0.457	0.0416
	FWSR	177.180	−25.063	1.233	−0.020	1.07	0.516	0.0283
	FWIL	109.750	−14.135	0.647	0.010	1.10	0.556	0.0255
	FWIR	70.833	−8.667	0.396	−0.006	1.09	0.559	0.0168
Interfacet height	IFHL	135.720	−20.994	1.201	−0.021	1.16	0.950	4.11E-08
	IFHR	97.381	−14.658	0.856	−0.015	1.33	0.942	1.06E-07
Interfacet width	IFWS	595.510	−85.587	4.185	−0.067	1.78	0.818	9.80E-05
	IFWI	312.070	−43.273	2.100	−0.033	2.50	0.605	0.0091
Facet orientations
Transverse angle	TASL	−629.850	106.150	−5.322	0.089	2.09	0.922	5.71E-07
	TASR	−468.340	81.873	−4.122	0.070	1.70	0.938	1.65E-07
	TAIL	−578.400	98.978	−4.951	0.082	1.65	0.892	4.45E-06
	TAIR	−394.580	70.418	−3.485	0.057	3.24	0.526	0.0254
Sagittal angle	SASL	−1384.100	260.400	−15.230	0.292	10.44	0.875	1.02E-05
	SASR	895.720	−180.630	10.957	−0.217	10.08	0.876	9.99E-06
	SAIL	24.358	24.433	−2.355	0.064	14.45	0.808	0.0001
	SAIR	−88.384	−14.160	1.824	−0.055	13.93	0.829	6.74E-05

SE in mm (for facet linear parameter) or in degree (for facet angular parameters).

The basic form of the prediction equations is y = C1 + C₂x + C₃x² + C₄x³, where y is the value of the facet parameter to be predicted and x is the value of the VBHP on each vertebral level. S, superior; I, inferior; L, left; R, right. Values in bold indicate facet parameters that show the same polynomial coefficients for thoracic and lumbar vertebrae.