ANATOMY AND PHYSIOLOGY OP THE HORSE ; S POOT. 423 
attached to it by cellular tissue; behind, it offers its largest 
and most remarkable surface ; above, on this face, it is chan- 
nelled by a great number of sinuous grooves for the recep- 
tion and support of a network of veins, and from the inter- 
spaces formed by these spring many small fibrous bands, 
which descend inwards to blend themselves with the plantar 
cushion ; nearer the base of the inner aspect of the cartilage 
these bands increase in size and width, and lower still the 
tissue of the cartilage itself becomes inseparably continuous 
with that of this cushion. Thus it will be seen that the most 
intimate relations exist between the lateral cartilage and the 
plantar cushion : first, through the medium of slender bands 
arising from the fibrous tissue of the upper part of the former, 
then of larger bundles, and, finally, by complete incorpora- 
tion of the two. 
The borders of these cartilages offer some points of in- 
terest. The upper or coronary border (fig. 7, n) is thin, 
and a little convex, and constitutes its highest and most 
elastic part ; on its inner face, near the posterior border, is a 
deep groove for the lodgment of the digital artery and vein, 
and within this is a small prominence into which is inserted 
the shortest branch of the navicular or lateral posterior liga- 
ment already described. The anterior border (fig. 9, m) 
passes obliquely downwards and backwards, thinned from its 
inner face, and forms an inseparable union with the anterior 
lateral ligament (fig, 7, /), by an intimate consolidation of 
their fibres ; at its upper corner, above the ligament, it gives 
off a somewhat wide fibrous band that proceeds transversely 
above the expansion of the anterior tendon, to which it closely 
adheres, and joins its fellow of the opposite side, thus com- 
pleting the union of the two cartilages in front of the foot. 
The posterior border (fig. 7, o) descends obliquely towards 
the heel, becoming gradually thicker, and meeting the in- 
ferior border, forms a prominent mass at that point which has 
been named the u cartilaginous bulb” (fig. 7, p). The infe- 
rior margin or base of the cartilage (fig. 7, u) contains im- 
bedded in its substance the extremity of the wing of the 
pedal bone, and is reflected backwards and inwards towards 
the sole to become continuous with the lower surface of the 
plantar cushion. 
The structure of these plates is essentially fibro-cartila- 
ginous; that is, fibrous tissue mixed up with cartilage-cells. 
The proportions in which these exist, however, vary exceed- 
ingly in different parts of the plate, though this is everywhere 
extremely elastic. The cartilaginous element is most abun- 
dant on the outer convex face of the plate, where it does not 
