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(SX) 
Charles R. Bardeen 
tissue the point of which extends toward the upper end of the femur. 
This he considers the anlage of the gluteus maximus, the piriformis, the 
gluteus medius and minimus, the tensor fascie late, quadratus femoris, 
and obturator internus. In the embryos of this period which I have 
studied I have not found an intimate union between the anlages of the 
gluteus medius group, the gluteus maximus, the obturator internus and 
the quadratus femoris groups. When differentiation of the muscles in 
this region begins the four anlages, though none of them sharply out- 
lined, seem to me fairly distinct from one another as I have attempted 
to show in Plate III, Figs. 1 and 2. 
In an embryo of 14 mm. (Plate VIII, Fig. 4) the m. tensor fasciz 
late is quite distinct from the rest of the group. Grifenberg states that 
at first it is closely connected with the anlage of the gluteus minimus. 
There is no connection between the anlages of the tensor fascie late and | 
that of the gluteus maximus. The separation of the gluteus medius from 
the gluteus minimus is marked best in the region through which the 
superior branch of the superior gluteal nerve passes out to end in the 
tensor fasciz late (Plate II, Fig. 3). The piriformis is still closely 
bound to the anlage of the two gluteals. I can find no connection be- 
tween it and the gluteus maximus such as that described by Grafenberg. 
The anlages of the two gluteal muscles and the piriformis pass distally 
into the proximal part of the back of the femur in the region where later 
the great trochanter will be developed. The gluteal anlages, closely ap- 
pled to the anlage of the acetabulum, extend to the femoral margin of 
the embryonic ilium. The piriformis extends over the peroneal nerve 
toward but does not reach the pelvis. It is to be presumed that in those 
instances in which the peroneal nerve passes through the piriformis the 
course of development of the muscle toward the sacrum takes place on 
each side of the nerve. The dense tissue between the peroneal and tibial 
nerves in this region may represent an interneural process of this kind. 
It is continuous with the piriformis anlage. 
Two distinct branches of the superior gluteal nerve may be seen. One 
of these extends to the tensor fasciz late, the other ends in the anlage 
of the gluteus medius. The nerve to the piriformis is likewise beginning 
to grow toward this muscle. 
In an embryo of 20 mm. (Plate VIII, Fig. 5) the great trochanter is 
becoming well marked, Bardeen, 05, and the attachments of the two 
deeper gluteal muscles and the piriformis begin to resemble those of the 
adult. The gluteal muscles have extended a considerable distance over 
the ilium the ala of which is much better developed than in the 14 mm. 
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