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

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.