504 THE RABBIT CHAP. 



the preaxial border is internal in the whole limb, and the 

 original dorsal surface looks, on the whole, forwards. 



Close to the proximal end of the femur, on its inner 

 (preaxial) border, is a rounded projecting head for arti- 

 culation with the acetabulum : the actual end of the bone 

 is formed by a strong process, the great trochanter, while 

 just distal to the head is a lesser trochanter, and opposite 

 this, on the outer (postaxial) side, a third trochanter. The 

 distal end of the bone bears two large condyles, separated 

 from one another by a notch, for articulation with the 

 tibia : this notch is continuous with a groove extending 

 for a short distance along the anterior (dorsal) surface 

 of the femur in which a large sesamoid bone (p. 502), 

 the knee-cap or patella, slides : the patella lies in the 

 tendon of the extensor muscles of the leg, and is con- 

 nected by ligament with the tibia. Two other sesamoid 

 bones, the jdbellce, occur on the opposite side of the 

 knee-joint. 



The tibia, or inner (preaxial) bone of the shank, is much 

 larger than the fibula, the distal half of which in the 

 adult becomes completely fused with it. The proximal 

 end of the tibia bears two slightly concave articular 

 surfaces for the condyles of the femur, and distally it 

 articulates with the tarsus : a prominent ridge the 

 cnemial crest extends along the proximal end of its 

 anterior (dorsal) surface. The slender fibula is attached 

 proximally to the tibia. 



The tarsus consists of six bones arranged in three rows. 

 In the proximal row (compare p. 51) are two tarsals, of 

 which the inner (preaxial) or astragalus probably corre- 

 sponding to two bones fused together, the tibiale and 

 intermedium has a large pulley-like surface for articula- 

 tion with the tibia ; while the outer (postaxial) calcaneum 

 orfibulare articulates with the fused end of the fibula, and 

 is produced into a strong heel or calcaneal process. In the 



