480 
LAMENESS IN HORSES. 
origin ; and though it may from spreading interfere with the 
motion of a joint, still does it not, that we know of, produce any 
affection of the synovial membrane. Spavin, on the contrary, 
seldom confines itself to the external or ligamentary tissues, but 
affects the synovial surfaces as well. And splint originates in the 
very joint — the fihro-cartilaginous — which it afterwards blocks up 
and grows from. 
Ringbone is either a ligamentary or a periosteal affection, or 
both. From the situation in which we commonly find it, and from 
the causes which are known to give rise to it, we believe it usually 
to be ligamentary in its beginning ; though, when once formed, and 
given to spread, no tissue, save the tendons, escapes conversion to 
contribute to the osseous mass ; and even the tendons themselves 
have been known to become partially ossified. In fact, when the 
exciting cause has been great, or when there exists an evident 
proneness in the constitution to ossific action, such is the extensive 
and varied form ossification takes on, that we can hardly say where 
it will make an end, so long as any soft tissues yet remain to be 
converted. Writing in the yeiar 1823 on this subject, with 150 
morbid specimens of the kind upon the table before us, we find we 
were led at the time to make the following remarks : — 
“ By far the most common seats of (ossific) disease are the pas- 
tern, coronet, and coffin bones. Out of the (said) 150 specimens 
there are 
“ 5 of complete anchylosis of the fetlock joint. 
“ 40 of complete anchylosis of the pastern joint. 
“ 18 of complete anchylosis of the coffin joint. 
“ The others are either simply encrusted, more particularly 
around their extremities, with layers of new bone, or are variously 
deformed by exostoses of different shapes, many of which are very 
large, and several of them confined to one side. Upon one of the 
pastern bones a complete osseous ring is formed, the result of ossi- 
fication of the theca of the flexor (perforatus) tendon. In nearly 
all, the disease appears to have taken its rise at, and to have 
spread from, the pastern joint ; there being but few specimens in 
which some (osseous) accretion is not to be observed around the 
lower end of the pastern hone and the upper one of the coronet hone; 
which is the kind of deposition that gives rise to ringbone*.” 
Here are facts which not only demonstrate the more common site 
of ringbone, but reflect a good amount of light upon its origin and 
nature and tendency as well. While the nidus of ringbone appears 
to be the ends of the two bones concurring to form the pastern joint, 
there exists a manifest disposition in parts adjacent to take on similar 
* “Elementary Lectures on the Veterinary Art,” vol. i, pp. 335-6. 
