’ 
80 THE SKELETON OF THE CAT. 
The shaft is nearly straight and cylindrical. <A roughfline 
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 (A). 
On its ventral surface is a nutrient foramen, directed proximad. 
The shaft gradually widens distad and ends in two condyles 
(¢@ and 7) which are continuous dorsad but separated ventrad 
by a deep notch, the intercondyloid fossa (2). The distal 
surface of the shaft and condyles is articular. This articular 
surface is larger on the lateral condyle (7). 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. 1, ~).—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 
