REGIONAL ANATOMY 31 
1. Tue Lareran Carritaces.—EKach is a flattened plate 
of cartilage, possessing two faces and four borders separated 
by four angles. 
The external face is convex, covered by a plexus of veins, 
and slightly overhangs the pedal bone. The internal face 
is concave, and covers in front the pedal articulation and 
the synovial sac, already mentioned as protruding between 
the antero- and postero-lateral ligaments of that joint. We 
have already remarked that this is a point of interest to be 
Fic. 16.--ExternaL Fack oF THE OUTER LATERAL CARTILAGE. 
1, External face of cartilage—(a) its upper border, (0) its posterior border, 
(c) its anterior border, (d) its inferior border; 2, the os pedis ; 3, wing of 
os pedis. 
remembered in connection with the operation for quittor. 
Below and behind, the internal face of the cartilage is 
united to the plantar cushion. 
The upper border, sometimes convex, sometimes straight, 
is thin and bevelled, and may easily be felt in the living 
animal. It is this border that the digital vessels cross to 
gain the foot, and the border is often broken by a deep 
notch to accommodate them. The inferior border is 
attached in front to the basilar and retrossal processes, 
