68 
ELEMENTS OF MAMMALIAN ANATOMY. 
enlarged extremities and a shaft whose cross-section is tri- 
angular. It articulates with the femur and fibula proximally 
Fic. 42. 
2 
a: 
h 
INNER OR 
MepraL ASPECT 
oF Ricut Fis- 
ULA. 
, Facet for tibia; 
ar, facet for as- 
tragalus ; ex, ex- 
ternal malleolus; 
h,head; s, shaft; 
t, articular sur- 
face for tibia; 
gr, groove for 
peroneus longus 
muscle, 
and the fibula and astragalus distally 
(Vig. 21). This is the longest bone in 
the cat’s skeleton. Between the concave 
condyles on the proximal end is a notch 
giving attachment to the crucial ligament 
of the knee-joint (Figs. 41, 46). 
The prominences of the lateral and 
medial aspects of the proximal extremity 
are the external and internal tuberosities 
respectively. Beneath the former is the 
facet for articulation with the fibula (Fig. 
41). The tubercle, a prominence on the 
cranial side of this extremity, is for the 
insertion of the ligamentum patelle, which 
is really the termination of the tendon of 
the quadriceps extensor muscle (Fig. 52). 
On the caudal aspect between the con- 
dyles is the popliteal notch. The sharp 
cranial of the bone forms the 
On the distal extremity is a proc- 
ess, the imternal malleolus, bearing two 
grooves, the more caudal of which shel- 
ters the tendon of the flexor longus digi- 
torum muscle while the other is for the 
tibialis posticus (Fig. 52). A facet is 
present on the lateral aspect of this ex- 
tremity for articulation with the fibula. 
The fibula in proportion to its length 
is the slenderest bone in the skeleton. 
border 
crest. 
It is the outer or lateral bone of the crus, and articu- 
lates proximally with the tibia and distally with the tibia 
and astragalus (Fig. 21). 
The proximal extremity is 
