992 
S. J. J. HARGER. 
ANATOMO-PATHOLOGIC STUDY OF RINGBONE AND 
SPAVIN AS INDICATED BY EXAMINATION OF 
PATHOLOGIC SPECIMENS. 
By S. J. J. Harger, D. V. M., Philadelphia, Pa. 
Read before the January meeting of the Keystone V. M. Association. 
There is some diversity of opinion as to the manner of pro¬ 
duction, the seat of the primary lesion and the order of progres¬ 
sion of the successive stages of the alterations of these diseased 
conditions. I anticipate that some of you may entertain vary¬ 
ing views upon these points, and I shall merely interpret the 
facts as they appear to have presented themselves to me from a 
series of specimens which I have examined.* 
i. Ringbone .—By this term I shall designate the exostoses 
having for their base the bones from the middle of the first pha¬ 
lanx to the os pedis (coronary ringbone). It is most fre¬ 
quently the lower extremity of the first and the upper end of 
the second phalanges—at the tuberosities where the lateral lig¬ 
aments are attached—that are the primary seat of the exostosis. 
In rare cases the latter may be confined to the pyramidal emi¬ 
nence of the third phalanx, involving the termination of the 
anterior extensor tendon of the phalanges and accompanied by 
a bulging of the superior border of the hoof. The distinction 
of high and low, true and cartilaginous ringbones of the English 
and French should, I believe, be discarded. 
Ringbones, according to the seat of the lesion, may be artic¬ 
ular and peri-articular. 
In the former the process is as follows : In the compact bone 
tissue a short distance under the articular cartilage, a rarefying 
ostitis takes place over an area appearing in transverse section 
as large as a pea or larger. The bone tissue becomes absorbed, 
leaving a cavity filled up with a more or less soft, embryonic 
tissue and blood vessels ; in other words, a rarefying ostitis. 
The process gradually extends towards the articular cartilage, 
* Specimens in the museum, Veterinary Department, University of Pennsylvania. 
