Charles R. Bardeen 291 
Frequently the perineal branch arises from the posterior cutaneous 
nerve in common with a large branch which passes to supply the medial 
surface of the leg (31 out of 110 instances). A branch of considerable 
size may arise in common with the perineal nerve and then pass upwards 
to be distributed over the medial margin of the gluteal muscle (15 out of 
110 instances). Two separate perineal branches are given off from the 
posterior cutaneous nerve infrequently (5 out of 110 instances). Rarely 
the perineal branch gives off rami both for the buttock and for the medial 
surface of the leg (2 out of 110 instances). 
Occasionally a root containing fibres destined mainly for the perineal 
nerve arises separately from the plexus, passes through the sacrotuberosal 
ligament and then joins the posterior cutaneous nerve immediately before 
this gives off the perineal branch (2 out of 94 instances). 
Femoro-popliteal branches.—As a rule several branches arise from the 
posterior cutaneous nerve as it passes down the back of the thigh. Those 
on the medial side of the nerve are the better developed. In the most 
common form of distribution (67 out of 94 instances) three or four 
branches arise from the medial side of the nerve between where it emerges 
from under the gluteus maximus muscle and the popliteal space. On 
the lateral side two to three branches are commonly given off. Another 
common type of distribution is one in which the upper half or two-thirds 
of the medial posterior surface of the thigh is supplied by a branch 
which arises in common with the perineal branch of the posterior cuta- 
neous nerve (24 out of 94 instances). This condition was found most 
frequently associated with an anterior type of plexus (type A, 1; type 
B, 4; type C, 9; type D, 5; type F, 1; type G, 1). 
In one instance soon after the posterior cutaneous nerve emerged from 
under the gluteus maximus muscle a long medial branch arose to supply 
the inner side of the leg as far as the knee, and a long lateral branch to 
supply a corresponding lateral area. ‘This was found on the right side 
of a subject with a normal, type D, plexus and a normal vertebral column. 
In another instance the posterior cutaneous after it emerged divided into 
two branches which extended to the knee and in addition a long medial 
branch arose from the perineal division of the nerve. This was found 
on the right side of a subject with a posterior, type G, form of plexus and 
13 thoracic, 5 lumbar, 4 sacral and 3 coccygeal vertebrae. In one instance 
the upper medial portion of the thigh was supplied by a nerve arising 
from the perineal branch of the pudic nerve. This was found on the 
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