PARALYSIS OF THE HIND LIMB. 
677 
seen in the above-named conditions, and because its onset is frequently 
masked by the symptoms of fractured pelvis. There is loss of function 
in the adductors, the pectineus and gracilis muscles, and inability to 
abduct the foot. It is sometimes possible to directly detect paralysis of 
the adductors. 
One recorded case was in a five year old mare, which became lame with¬ 
out visible cause. In walking, and still more so in trotting, the right hind 
foot was strongly adducted. The hip-joint was markedly flexed, and the 
stifle drawn upwards and outwards, as in stringhalt. When backing 
there was difficulty in moving the right foot, but weight was placed on 
the limb as usual. Recovery occurred in between four and five months, 
during which strychnine was administered. The case described by 
Nocard (see section on “ Fracture of the Pelvis” : sub-division, “ Treat¬ 
ment”) as due to compression of nerve trunks by the callus, resulting 
from a fracture through the obturator foramen, may really have been 
one of obturator paralysis. There was atrophy of the adductor group of 
muscles, and a peculiar lameness. 
Obturator paralysis has several times been reported as following 
tumour formation in the course of the nerve, especially in grey or white 
horses, the subjects of melanosis. 
W. Willis has recently (1908) described two cases of obturator paralysis, 
and referred to others as having been seen. In each instance there 
existed a swelling, which later developed into a callus over the pubis at 
the point where the obturator nerve crosses that bone. In mares it could 
be detected by examination through the vagina. W illis at first diagnosed 
these cases as “ fractured pelvis,” as indeed they were. The average 
duration of the cases appears to have been about three months, and the 
paralysis appeared to march concurrently with the development of the 
callus, marked abduction of the limb, its principal symptom, appearing 
as the soft callus increased in size and diminishing as the callus 
became smaller and more fully ossified. In one instance, though the 
animal was able to work, a certain degree of abduction continued for 
a year. 
VII.-THROMBOSIS OF THE POSTERIOR AORTA AND 
OF ITS BRANCHES. 
Aneurism of the anterior mesenteric artery is common in horses, and 
loosened particles of the thrombus may be hurried with the blood-stream 
into the posterior aorta and its branches, which then become throm¬ 
bosed. Proeger saw thrombosis in a cow in consequence of endocarditis. 
Stoppage of small vessels near the femoral or pelvic arteries by emboli of 
