THE UNIVERSITY OF CALGARY Eric Snively A ... - Ohio University

of MT III (Figure 4.4, pinpointed by the red lines). The significance of strain in
each location corresponds to the respective morphologies of these regions.
Purple element edges indicate strain along the lateral and rnedial surfaces of
the distal third metatarsal, where the bon8 slants proximally towards its
midsagittal plane. The location of these indicated strains is congruent with that of
osteological correlates for ligaments in the tyrannosaurid metatarsus, as
described in Chapter 3 (Figures 3.6-3.8).
Compressive strain is also prominent where MT III narrows to become a
proximal splint (Figure 4.4). Contour plots of relative strain magnitudes on MT III
(Figure 4.5) corroborate the high strain on the splint during compressive loading,
in this case four times body weight. The concentration of strain energy in this
region is consistent with higher stresses per unit cross section, as would be
expected in particularly gracile regions of the bone.
II. The metatarsus at 50 degrees to the substrate.
Figure 4.6 depicts contour plots of strain magnitudes, assuming that MT III is
angled, held rigid at the proximal end, and loaded by a ground reaction force
perpendicular to the substrate. Under this loading regime, the proximal spiint of
MT III experiences high bending strains. In Figure 4.6, bright yellow and gray in
this region show displacement along the y axis, which signifies antenorly directed
strain. Elements in this narrow region are relatively small, indicating that the
results refiect potential in vivo strains rather than artifacts.
The numerical results output h m MARC are insufficiently legible to determine
if bending strain was sufiicient to break the proximal splint. However, the buildup