424 ANATOMY AND PHYSIOLOGY OF THE HOUSERS FOOT. 
contract any adhesions, but the fibrous tissue gradually pre- 
dominates as we approach the inner face, which forms such 
important and numerous relations with the adjacent textures. 
Towards the upper anterior portion the cartilage is most ap- 
parent, but where it becomes fused with the lateral ligament, 
at its lower border, and in its inner reflection towards the 
plantar cushion, it is almost entirely a strong fibrous mem- 
brane, which varies in thickness and density in different situa- 
tions. At has been remarked, the presence of this fibrous 
tissue permits the strongest adhesions being contracted with 
all the neighbouring parts by the extension of the fibres, as 
powerful ligamentous bands, into their structure. 
Where the cartilaginous element prevails — and which is 
indicated by its bluish-white colour, the presence of large 
cells, and an almost homogeneous matrix — the blood-vessels 
that nourish the plate are very few ; but, on the contrary, 
where it is least abundant or entirely absent, as at the lower 
and posterior parts, it is most plentifully supplied. 
The tendency of these cartilages to become more or less 
converted into bone is well known to the majority of horse- 
men ; and though this transformation is generally the result 
of inflammation — acute or chronic — induced by external or 
internal agencies, yet I have met with traces of calcareous 
deposition in the lateral cartilages of horses that had not 
shown any symptoms of such a change taking place. Any 
portion of the plate may become the centre of this calcareous 
infiltration ; there may even be several centres, or the 
whole plate may be invaded by minute deposits of bony 
matter ; but as a rule, when not due to external injury, I have 
observed that the alteration begins at or near the fixation of 
the cartilage into the pedal bone (fig 7, u) , and proceeds 
upwards ; it would also appear to manifest itself first among 
the cells in the vicinity of the fibres that pass from the inner 
surface of each plate to join some of the textures at the pos- 
terior part of the foot, and even involves the origin of these 
fibres. I think it somewhat remarkable, however, that the 
fibres themselves, after leaving the plate, are but seldom, if 
ever, subjected to ossific change, which seems to be most 
frequent in those portions where the cartilage-cells are pre- 
dominant. I do not remember meeting with any morbid 
specimens in which the reflections of the cartilages into the 
plantar cushion were affected, and these are chiefly fibrous. 
In reference to this matter, and also in relation to the 
anatomy of the foot, it is well to note that in the posterior 
extremity the lateral cartilages are smaller and thinner than 
those of the fore foot, and also differ from them in texture 
