NEURECTOMY in spavin. 
737 
in no other disease are diagnostic errors so frequent as here, for even the 
most careful examination often leads to no definite conclusion. Serious 
methods of treatment are only applied to serious conditions, i.e., to cases 
in which disease has made extensive progress, whilst the milder cases are 
blistered or fired; especially in the army, where firing and blistering are 
greatly relied on. 
In a number of cases where the swelling is old, large, diffuse, and 
especially when it extends far forwards towards the bend of the hock, 
firing, even if repeated, and section of the 
terminal branch of the flexor metatarsi tendon 
fail, or only yield a very modified success ; 
lameness persists or is remittent, being less 
marked after a certain amount of exercise 
than on leaving the stable, though some¬ 
times it is equally pronounced before and 
after exercise : in these rebellious cases double 
neurectomy of the posterior and anterior tibial 
nerves, the latter a branch of the external popli¬ 
teal, has been recommended. This treatment 
of obstinate spavin by neurectomy is based on 
the following anatomical facts :—Opposite the 
point of the calcis the posterior tibial nerve 
divides into two parts, the internal and ex¬ 
ternal plantar nerves. Behind the hock-joint 
the external plantar nerve gives off a fairly 
large branch, which passes under the tendon 
of the flexor perforans, and detaches several 
twigs, of which some ramify over the surface 
of the joint, whilst others penetrate into it. 
In front of the lower extremity of the tibia 
the tibial nerve gives off several branches, 
which enter the joint. 
In neurectomy of the anterior tibial, the 
point selected is at the external surface of the lower part of the thigh, 
a hand’s breadth above the point of the hock. The anterior tibial nerve 
is situated on the deep surface of the extensor pedis, between this muscle 
and the thin muscular portion of the flexor metatarsi which separates it 
from the anterior tibial artery, and from its large satellite vein—vessels 
which lie directly on the anterior surface of the tibia, where they are 
surrounded by a thick layer of connective tissue (see section, fig. 269). 
The method is as follows :—The point of operation being prepared, 
the skin and subjacent aponeurosis are incised for a distance of 2J 
to 3 inches, opposite the external margin of the extensor pedis 
Fig. 270. —Rubber cord applied 
to tliigli to check bleeding. In 
neurectomy of the posterior 
tibial nerve the cord would be 
applied rather higher. 
V.S. 
3 B 
