332 THE SKELETON OF THE RABBIT. 



surface of the bone, is a deep pit, the trochan- 

 teric or digital fossa. 



On the inner or preaxial side of the bone, 

 immediately below the head, is a rough ridge, 

 the lesser trochanter ; opposite to which on 

 the outer or postaxial side is the prominent 

 third trochanter. 



The lower or distal end of the bone 'bears 

 two large condyles which articulate with the 

 tibia. These are separated from each other 

 by the intercondylar notch, which is con- 

 tinuous with a deep groove on the front of 

 the bone, along which the patella slides. 



ii. The patella, or knee-pan, is a large sesamoid 

 bone in the tendon of the extensor muscles of 

 the leg. It is connected by ligaments with 

 the tibia, and slides in the groove on the front 

 of the lower end of the femur. 



At the back of the knee-joint are smaller 

 sesamoids, the fabellae. 



2. The leg contains two bones, which are very unequal in 

 size, and in the adult are fused together distally. 



i. The tibia, or preaxial bone of the leg, is a stout 

 and straight bone, the longest in the body. 

 Its enlarged proximal end, which is triangular 

 in section, bears on its upper end two oval 

 surfaces for articulation with the condyles of 

 the femur. Below the head is the prominent 

 cnemial crest, extending some distance down 

 the anterior surface of the bone. 



The distal end of the tibia, which is 

 indistinguishably fused with the lower end 

 of the fibula, bears an articular surface for 

 the astragalus. 



ii. The fibula, or postaxial bone, is very slender : 

 its proximal end is distinct, and articulates 



