Fig. 8.

Predicted Iliofemoralis group muscle moment arms for hip (a, d) flexion–extension, (b, e) abduction–adduction and (c, f) long axis rotation in Lesothosaurus and other dinosaurian bipeds over a range of hip joint flexion–extension angles. The cranial part of iliofemoralis approximately corresponds to the avian iliotrochantericus caudalis; the caudal part of iliofemoralis approximately corresponds with the avian iliofemoralis externus. Pelvis, femur and IFM in right lateral view in (g) Lesothosaurus, (h) Allosaurus and (i) Struthio (not to scale). IFMa is located much farther cranial to the joint centre in the ostrich (i), causing higher medial rotation moment arms. ABD-ADD; abduction/adduction; FL, femoral length; Flex-Ext, flexion/extension; LAR, long axis rotation; MA, moment arm.