172 
THIRTEENTH REPORT. 
berculosis so that the muscular system was poorly developed. In the 
preliminary dissection a small rounded swelling was noted in the right 
inguinal region, approximately under the middle of Poupart’s ligament. 
This was thought to be a hernia at first, but upon complete dissection a 
patulous finger-like process was seen extending downward and inward 
from the external inguinal ring, lying anterior to the closely attached 
round ligament, and lateral to the genital branch of the genito-crural 
nerve. 
The rounded finger-like process was a projection from the peritoneum 
and had carried with it not only the overlying fascia layers but also 
some of the muscular. The occurrence of the finger-like process is well 
known as a persistent processus vaginalis or canal of Nuck. It was 5 cm. 
long and 1 cm. in diameter. It was covered not only by the enveloping 
fasciae but distinct muscular loops were seen radiating down 
along its sides to enclose the whole in a basket of closely interwoven 
muscular fibers. Most of these fibers descended along its lateral side from 
the middle of the ligament of Poupart, a few extending from the anterior 
layer of the rectus sheath and the pubic spine. The whole arrangement 
was very similar to that seen in the male specimens on neighboring 
tables. 
Small twigs from the genital branch of the' genito-crural nerve entered 
the muscle medially supplying it. The relation to the ilio inguinal nerve 
could not be determined as it had been destroyed in dissection. The 
muscular fibers were closely associated with the accompanying round 
ligament, on which a few fibers sometimes pass to be described as the 
Cremaster muscle in the female. 
The embryological condition by which this anomaly can be explained 
has to do with the changes occurring in the descent of the testes and 
ovaries. As they commence their descent an independent change oc- 
curs in the lower pubic region resulting in the formation of a shallow 
inguinal bursa lined by a processus vaginalis of the peritoneum. In the 
male this processus vaginalis is carried down by the descent of the 
testis and is made use of as its tunica vaginalis. In the female the orig- 
inal processus vaginalis usually disappears, in this case however per- 
sisting as a canal of Auck and bearing on itself fibers of the abdominal 
muscles carried down in its growth. 
The whole anomaly, then, represents the failure of an embryological 
structure to be absorbed and ils persistence acquiring the adult condi- 
tion of the opposite sex. 
April 2. 1911 
