CHRONIC SYNOVITIS—DROPSIES. 339 
complicated with periostitis of the trochanter, osteophytes develop, the 
parts are swollen, the lameness is excessive (Williams). Against this com- 
plication, all treatment fails. 
Vi—Sheaths of the Hock. 
The synovials which belong to the joints of the hock, and assist in the 
sliding of the tendons, are often affected with dropsy. There are the /arsai, 
cunean, calcanean and the pretarsal thoroughpin. The latter is formed 
by the distension of the synovials of the extensor of the phalanges. 
The sarsal thoroughpin, due to 
the dropsy of the tarsal sheath, is 
observed on animals which do hard 
work. It is characterized by three 
swellings having a constant situa- 
tion: two, supratarsal, result from 
the distension of the superior cul 
de sacs of the synovial, in the hol- 
low of the hock, between the ten- 
don Achilles and the perforans ; 
the internal is generally more de- 
veloped than the external. The 
third, metatarsal, surrounds the 
flexor tendons, in the upper third 
of the cannon; it forms a monili- 
form dilatation, not very apparent 
on account of the resistance of 
the tissues that cover it; some- 
times it resembles somewhat the 
jarde (the curb). Tarsal thorough- 
pin may assume enormous dimen- 
sions. It has been seen with such ; 
proportions that, during walking, the skin which covers the internal swell- 
ing rubs and chafes against the hock of the opposite side. The diagnosis 
is doubtful only when both the articular and tendinous synovials commu- 
nicate together. 
Cooling and astringents have been used; but the recoveries which they 
seemed to have given were specially due to the long rest given with them. 
When the thoroughpin is recent, blisters and the various liniments ought 
to be tried; but with old and large thoroughpins, cauterization is the 
classical treatment, either in lines or in deep points. In 1830 already, 
Dard punctured these dilatations with the straight bistouri and applied 
Fig. 82,—Tarsal thoroughpin.. 
