Table 9. Estimates of extensor muscle masses (total acting about each joint in one hindlimb) for tyrannosaur specimens.

	Extensor mass as % body mass per joint
Joint	Carnegie	Sue	Stan	MOR	Jane
Hip min	9.05	9.10	12.3	11.9	13.2
Hip max	8.79	10.7	15.1	13.9	17.6
Knee min	4.10	4.40	5.68	5.76	4.94
Knee max	3.29	4.80	7.07	6.84	7.27
Ankle min	2.33	1.90	2.52	2.42	2.46
Ankle max	2.55	2.00	3.22	2.99	3.93
TOTAL MIN	15.5	15.4	20.5	20.1	20.6
TOTAL MAX	14.6	17.6	25.4	23.7	28.8

As described in the methods we estimated muscle volumes from limb segment volumes (minus bone volumes, which were small fractions (∼5%) of the segment volumes) as in Hutchinson et al. (2007). We adjusted those non-bony segment volumes by multiplying them by the percentages of segment mass observed in extant Sauria (based on dissection data from Hutchinson, 2004a,b) that are dedicated to extensor muscles. The hip extensor estimate was 54% of thigh mass (plus CFL mass from Table 8), the knee extensor estimate was 34% of thigh mass, and the ankle extensor estimate was 47% of shank mass.