Table 3.

Dimensions and inertia properties of the sheep stapes in comparison with the human stapes

Description	Symbol	1Sheep	2Ref. human	Sheep/human
Long length of footplate	a (mm)	2.03 ± 0.12	2.81 ± 0.16	0.72
Short length of footplate	b (mm)	0.93 ± 0.06	1.27 ± 0.11	0.73
Long length/short length of footplate	a/b	2.20 ± 0.19	2.22 ± 0.20	0.99
Footplate area (medial surface)	AFT (mm2)	1.54 ± 0.14	3.03 ± 0.33	0.51
Projected footplate area (to xSyS-plane)	AFTproj (mm2)	1.45 ± 0.13	2.86 ± 0.32	0.51
Projected footplate area/Footplate area	AFTproj/AFT	0.94 ± 0.01	0.94 ± 0.02	1.00
Equivalent diameter of footplate area	dFT_eq (mm)	1.40 ± 0.06	1.96 ± 0.11	0.71
Equivalent diameter of projected footplate area	dFTproj_eq (mm)	1.36 ± 0.06	1.90 ± 0.11	0.72
x-coordinate of the C.O.M	xc (mm)	-0.12 ± 0.07	0.00 ± 0.09
y-coordinate of the C.O.M	yc (mm)	0.00 ± 0.04	−0.12 ± 0.09
Height (z-coordinate) of the C.O.M	hc (mm)	0.76 ± 0.05	1.22 ± 0.16	0.62
Total height of stapes	h (mm)	2.10 ± 0.10	3.28 ± 0.21	0.64
Height of C.O.M./total height	hc/h	0.37 ± 0.02	0.37 ± 0.04	1.00
Total height/equivalent diameter of footplate	h/dFTproj_eq	1.55 ± 0.11	1.72 ± 0.12	0.90
Volume	VS (mm3)	0.83 ± 0.08	1.43 ± 0.24	0.56
Mass	mS (mg)	1.75	3.2	0.55
Mass ratio relative to total ossicular chain	mS/mMIS	0.08	0.05	1.57
Average density	ρS (mg/ mm3)	2.11	2.24	0.94
Minimum principal moment of inertia	ISMIN (mg·mm2)	0.49 ± 0.13	2.2 ± 0.49	0.22
Medium principal moment of inertia	ISMED (mg·mm2)	1.05 ± 0.20	4.6 ± 1.18	0.23
Maximum principal moment of inertia	ISMAX (mg·mm2)	1.37 ± 0.29	6.3 ± 1.53	0.22
Ratio of ISMIN–ISMAX	ISMIN/ISMAX	0.36 ± 0.05	0.35 ± 0.04	1.03
Ratio of ISMED–ISMAX	ISMED/ISMAX	0.77 ± 0.05	0.74 ± 0.04	1.04

¹n = 8 except for mass (n = 2 for mass; the average density was obtained from mean values of volume and mass)

² From Sim et al. 2008 and Sim et al. 2013 except for mass and average density (mass of a stapes was measured; the average density was calculated from the mean values of volume and the measured mass)