THE HIND 1.IMH AND FOOT 



61 



-F 



Y.PM. 2015 



d d 



Fig. 28. — Left tibia and fibula of Monoclonius (Centrosaurus) flexus. A, anterior view; B, posterior view; 1/6 



natural size, f, proximal extremity; d, distal extremity; a, astragalus; c, calcaneum ; cc, cnemi.il crest; /, fibula; 

 ic, inner condyle; oc, outer condyle; t, tibia. 



Fibula 



(Fig. 28) 



The fibula is a long, slender bone with a more or less cylindrical shaft and flattened, dilated 

 extremities which lie in planes at right angles to each other. The over-all length is somewhat less 

 than that of the tibia, although the proximal end rises above the articular face of the latter. Prox- 

 imally, the fibula lies against the outer rear surface of the tibia; distally, against the outer front 

 surface. The distal end articulates with the calcaneum. The shaft of the bone, aside from a certain 

 torsion, is curved toward either end in the reverse direction, proximally toward the rear, and distally 

 toward the front. 



Dimensions of Tibia and Fibula 



C. flexus Y.P.M. C. cutleri C. nasicornus M. crassus 



Total length of tibia including astragalus .. 552 mm. . 500 mm. 600 mm. 538 mm. 



Length of fibula 527 460 560 505 



Width of tibia 



Proximal end 222 230" 



Mid-shaft 93 



Distal end 220 184" 



Width of fibula 



Proximal end 54 



Mid-shaft 34 



Distal end 82 



35 Estimated from Cope's figure. 



