422 ANATOMY AND PHYSIOLOGY OF THE HORSE'S FOOT. 
spring from, are attached to, and mainly rely for their integrity 
upon, the os pedis, around whose upper margin, and on or 
between the wings of which they are principally situated, to 
a great extent making up the posterior aspect of the foot, and 
forming no inconsiderable feature on its front and sides } 
where they constitute nearly the whole of the coronet. 
Though in reality but one, by reason of their apparent 
continuity and similarity of function, yet because of their 
dissimilar organization and disposition, we will divide them 
into three portions — the elastic cartilages , coronary cushion, 
and plantar cushion, by which designations they will, perhaps, 
be easier recognised and described. 
The Lateral Cartilages of the Foot (figs. 7, m; 8 ,o; 9 ,//) . — 
From among the many names which have at various times been 
given to these bodies, such as “ scutiform appendices of the 
third phalanx/' fibro-cartilages of the third phalanx," 
“ cartilaginous plates," ie great cartilages of the foot," “ great 
podal cartilages," “ fibro- cartilaginous prolongations of the 
os pedis," &c., I select the above designation as at once 
simple and concise, if not absolutely exact, when referring to 
the lateral portions of the elastic apparatus of the foot. 
The description of these parts ought, perhaps, to have been 
entered upon when speaking of the pedal bone, as they are 
apparently only prolongations of that phalanx ; but I have 
purposely deferred noticing them until now, because of their 
forming a portion of the complex elastic arrangement of the 
foot which I thought most convenient to examine as a whole, 
forming, as it does, a wide and deep bed, surrounding byits con- 
stituent portions more or less of the foot in particular regions. 
Rising almost perpendicularly from each side of the os 
pedis, to the basilar and retrossal processes of which they are 
attached, but more particularly the first, these cartilages, 
peculiar to solipeds, completely encircle its extended wings 
in the form of a scuti or shield, from each margin of the 
pyramidal process in front to beyond the retrossal processes 
posteriorly, beneath which they are reflected inwards towards 
each other. Each cartilage is a somewhat thin plate, in shape 
an oblique parallelogram, extending as high as the joint formed 
by the large and small pastern bones, and as far back as the point 
of the coronet; its outer surface (fig. 9, m), unevenly convex, can 
be felt for some distance above the hoof during life, and is 
pierced with numerous small slanting openings for the passage 
of vessels, more especially in its lower superficies ; its inner 
face (fig. 8, 6) is concave and adapts itself to the parts with 
which it comes in contact ; in front, it is in close proximity to 
the fibrous capsule of the joint of the foot, and is, indeed, 
