Table 2.

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

Parameter	Abbreviation	C1	C2	C3	C4	SE	R2	P-value
Facet dimensions
Height	FHSL	−4.775	4.189	−0.309	0.007	1.18	0.647	0.0046
	FHSR	33.916	−2.520	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	5.61E-07
Width	FWSL	381.760	−59.777	3.175	−0.056	0.7	0.771	0.0061
	FWSR	244.770	−36.675	1.890	−0.032	0.46	0.850	0.0011
	FWIL	383.000	−61.279	3.325	−0.059	0.60	0.788	0.0045
	FWIR	314.610	−50.508	2.763	−0.050	0.60	0.703	0.0164
Interfacet height	IFHL	45.467	−5.543	0.329	−0.005	0.79	0.970	2E-06
	IFHR	−56.782	11.697	−0.628	0.013	0.76	0.973	1.35E-06
Interfacet width	IFWS	744.410	−111.100	5.625	−0.094	1.47	0.880	0.0005
	IFWI	620.110	−95.960	5.0701	−0.088	0.89	0.868	0.0007
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	−772.290	131.960	−6.800	0.116	1.40	0.930	5.73E-05
	TAIR	−294.800	53.407	−2.529	0.040	1.98	0.785	0.0047
Sagittal angle	SASL	998.880	−149.700	8.0381	−0.143	1.04	0.952	1.31E-05
	SASR	−1084.000	160.740	−8.4545	0.147	1.41	0.904	0.0002
	SAIL	−2549.600	463.78	−27.063	0.521	8.47	0.849	0.0012
	SAIR	2375.500	−434.840	25.490	−0.493	8.20	0.862	0.0084

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.