Figure 1 in Age and growth dynamics of Tyrannosaurus rex

Figure 1. Bone histology of Tyrannosaurus rex. Transverse thin sections of long bone mid-shafts. (a) MOR 009, composite quadrants of tibia. COR, cortex; MA, major axis; MED, medullary cavity; MI, minor axis; R, radius. (b) MOR 1128, external cortex of tibia, showing typical fibro-lamellar bone and LAG (arrow). In this region the bone is growing at an average rate of 11.2– 17.4 цm d―1, comparable to very rapid growth in the developing mallard (Castanet et al. 1996). (c) MOR 1152, external cortex of fibula showing tight spacing of eight LAGs (arrows) throughout the cortex. The round structures with small centres interrupting the matrix are mature secondary osteons that progressively invade the cortex centrifugally. (d) Detail of (c) showing the outermost cortex with tighter spacing of nine more LAGs. External to these LAGs is a compact area of low vascularity that may reflect the final stages of very slow growth. (e) MOR 1152, outer cortex of femur showing the final closely spaced three LAGs that may correspond to the outermost layer of the fibula. Scale bars: (a) 2 cm; (b–e) 1 mm.