OPEN SYNOVIAL CAVITIES. 415 
about with tendon. Each of the tendons, when crossing the joint, is 
embraced in a synovial sheath. From such information, it will instantly 
be seen how far more likely a sheath is to be lacerated than the joint is 
to be punctured. 
The single point where the joint could be entered without severing 
tendon, lies rather on one side than directly in the center. The vulner- 
able spot is therefore not exposed to the full force of the blow. To lay 
bare the joint by an ordinary fall several parts must be divided. Rarely 
is an accident witnessed of so fearful an extent. Generally that which 
is spoken of as open joint proves to be no more than 
punctured sheath, the presence of synovia being 
commonly accepted as the proof. But when the 
joint is really laid open, the immense flow of syno- 
via—so many sheaths being severed—should at once 
prove the fact. 
The probe must next be used. In the first in- 
stance it should be employed to ascertain whether 
the fall has left any purse or sac at the inferior part 
of the joint. All which was enforced respecting 
the use of metallic wire to a raw wound must here 
be observed. The probe had better be altogether 
discarded than employed with the smallest approach to rudeness. 
The suspected sac having been discovered, a large spatula is placed 
below the knee. A knife with a keen point, but with the edge only 
sharpened for one-third of its length, is 
to be used. Upon the cutting point of 
the knife a piece of beeswax is firmly 
moulded. The wax answers the pur- 
pose of a temporary probe; the blade, 
thus guarded, is cautiously inserted be- 
neath the loose flap of skin. When the 
bottom of the pouch is reached, a cer- 
tain amount of resistance will be encoun- 
tered; through this the knife is driven. 
The force cuts in twain the wax, and AG 
pushes through the integument the blade, sz ee eee 
which the spatula guides from the leg. JOINT. 
This operation should be performed 
quickly; the hand should simply be carried downward, and then brought 
upward when all is concluded; care, however, being taken that the 
withdrawal of the knife does not injure any part save those it was 
designed to cut. 
PROBING BROKEN KNEE. 
