284 ZOOTOMY. 



on the pre-axial border, immediately distal to the head ; 

 and a small third trochanter on the post-axial (external) 

 border, slightly beyond the great trochanter. On the head 

 is a shallow pit for the attachment of the ligamentum 

 teres ( 471). Its distal extremity presents an internal 

 condyle (pre-axial) and an external condyle (post- 

 axial), separated from one another by the intercondylar 

 notch, which, with the condyles, forms the articular surface 

 for the tibia ( 96) and patella ( 95). The internal and 

 external tuberosities are small roughened projections, 

 situated, the first on the pre-axial, the second on the 

 post-axial, border of the distal extremity of the femur, 

 close to the condyles. In the young animal the whole 

 distal end of the femur is formed by an epiphysis, while at 

 the proximal end are two epiphyses, one forming the head, 

 the other the greater trochanter. 



94; Two nodular sesamoid bones, or fabellae, occur in 

 connection with the distal end of the femur, a smaller pre- 

 axial, and a larger post-axial, both being situated quite on the 

 posterior (ventral) aspect of the bone. 



95. The patella (a sesamoid), a small nodule of bone, 

 fitting against the pre-axial end of the intercondylar notch, 

 and connected by ligament to the tibia. 



96. The tibia, or larger bone of the shank, so placed 

 that its true dorsal surface looks forwards and slightly down- 

 wards, and its pre-axial border inwards. Its proximal ex- 

 tremity presents two slightly concave articular surfaces 

 for the conOyle of the femur, and two roughened tuberosities 

 on its pre-axial and post-axial borders respectively. A 

 prominent ridge, the crest of the tibia, extends along the 

 proximal end of the (anterior) dorsal surface of the bone. 

 Its distal extremity presents two articular surfaces, one 

 pre-axial, and pulley-like, for the astragalus, the other post- 



