292 The Nerves and Muscles of the Leg 
right side of a subject with a normal, type D, plexus and a normal 
skeleton. 
Terminal branches.—The absence of a posterior cutaneous nerve has 
been reported, but this condition I have not seen. In one instance 
(308-R) the terminal branches could not be followed as far as the knee 
by gross dissection. In the great majority of instances (81 out of 110) 
the terminal branches could be readily followed into the upper third of 
the back of the leg. But rarely was there found the branch described in 
Poirier and Charpy’s anatomy as extending to anastomose with the sural 
nerve. In 21 out of 110 instances the chief terminal branch extended on 
the medial side of the leg well into the middle third of the back of the leg. 
In 8 instances out of 110 the chief terminal branch could be followed 
nearly to the medial malleolus. This extensive distribution of the pos- 
terior cutaneous nerve of the thigh was found twice associated with the 
B type of plexus, once with the C type, four times with the D type, and 
once with an F type. No obvious relation therefore exists between the 
extent of distribution of the posterior cutaneous nerve and the form of 
the plexus from which it springs. This also is true of relations to the 
origin of the nerve from the sacral plexus and to race, sex, and side of 
body. 
2. Perforating Cutaneous Nerve. 
A distinct perforating cutaneous nerve arising from the 2d and 3d 
sacral nerves and passing through the sacro-tuberosal ligament to supply 
the skin over the medial margin of the buttock was found in but 8 in- 
stances out of 94. To what extent this small percentage is to be attrib- 
uted to lack of sufficient care in dissection cannot at present be stated. 
Only the better charts have been used in this tabulation. Eisler found 
the nerve in 22 out of 34 instances. 
In one instance the perineal branch of the posterior cutaneous passed 
beneath the sacro-tuberosal ligament on the way to its destination. 
3. Cutaneous Branches of the Peroneal Nerve. 
a. N. Cutaneus surae lateralis—This nerve arises in the popliteal 
space and runs down over the lateral head of the gastrocnemius to supply 
the lateral cutaneous area of the leg and usuaily sends a branch to 
anastomose with the n. cutaneus sure medialis to form the sural (ex- 
ternal saphenous) nerve. This form of distribution was found in 38 out 
of %6 instances. In 30 out of 76 instances the communicating branch to 
