8o THE SKELETON OF THE CAT. 



The shaft is nearly straight and cylindrical. A rough line 

 is continued along its ventral surface from the lesser trochanter, 

 and a similar line along its lateral surface from the greater 

 trochanter; these unite ventrad to form the linea aspera (//). 

 On its ventral surface is a nutrient foramen, directed proximad. 



The shaft gradually widens distad and ends in two condyles 

 (/ andy) which are continuous dorsad but separated ventrad 

 by a deep notch, the intercondyloid fossa (). The distal 

 surface of the shaft and condyles is articular. This articular 

 surface is larger on the lateral condyle (/). The part of the 

 articular surface on the end of the shaft (patellar surface) is 

 for the patella; that part of it on the condyles and separated 

 by the notch is for the tibia. 



On the lateral surface of the lateral condyle is a slight 

 prominence, the lateral epicondyle (/), and on the medial sur- 

 face of the medial condyle is another prominence, the medial 

 epicondyle ; both are for the attachment of ligaments. 



Patella (Fig. I, r). The patella is a small flat bone with 

 a pear-shaped outline, having its apex distad. It lies against 

 the articular surface at the lower end of the shaft of the femur. 

 It thus covers the knee-joint. The inner surface is smooth and 

 convex from side to side, but concave in a proximodistal line. 

 It fits against the lower end of the femur. Its outer surface is 

 rough and concave. It is a sesamoid bone inserted in the 

 tendon of the quadriceps femoris muscle. 



Three other sesamoid bones are found in the region of the 

 knee (see Fig. 61, p. 89). Two are in the tendons of the 

 gastrocnemius muscle, proximad of the two condyles of the 

 femur. The third is in the tendon of the popliteus muscle, 

 just laterad of the lateral condyle of the femur. 



Tibia (/, Fig. 57). The tibia is the longer of the two 

 bones of the leg between the knee and the ankle, and is the 

 longest bone of the body. It has a triangular shaft and 

 enlarged proximal and distal ends. 



The proximal end is curved ventrad and projects into two 

 prominences, the tuberosities, on either side. Each tuberosity 

 bears on its proximal end an articular facet for the condyles of 

 the femur; these are known respectively as the lateral and 



