58 H. D. SENIOR 
the following description the term a. ischiadica has been re- 
stricted to the part of the axial artery proximal to the site at 
which it is subsequently joined by the a. femoralis. This 
restriction has necessitated the use of a new term for the part 
of the axial artery which extends from the hiatus tendineus 
(the approximate site of the femoro-ischiadic junction) to the 
point (in the neighborhood of the distal border of the m. 
popliteus) at which the a. interossea begins. 
An examination of the popliteal portion of the human axial 
artery shows that its distal part does not lie upon the posterior 
surface of the m. popliteus as does the distal part of the adult 
a. poplitea, but upon the anterior surface of that muscle. It 
seems clear, therefore, that the distal part of the a. poplitea of 
the majority of adult mammals, which lies upon the anterior 
surface of the m. popliteus represents a persisting portion of the 
embryonic axial artery. On this account the name a. poplitea 
profunda has been used in the following pages to designate 
entire popliteal section of the human axial artery. 
The solution of Zuckerkandl’s difficulty regarding the differ- 
ence of the mutual relations between the a. poplitea and the m. 
popliteus in man on the one hand and’in the majority of other 
mammals upon the other has thus been furnished by determining 
the course of the popliteal portion of the axial artery of the 
human embryo.! 
The part of the adult human a. poplitea which extends from 
the hiatus tendineus to the origin of the a. genu inferior 
medialis is a direct survival of the embryonic a. poplitea pro- 
funda. The part of that artery which lies upon the posterior 
surface of the m. popliteus is derived from an embryonic vessel 
of later formation referred to in the following pages as the a. 
poplitea superficialis. 
1 Arteria poplitea. Ein Stiick dieser Arterie lagert bei den Halbaffen und den 
Primaten auf der freien (dorsalen) Fliiche des Musculus popliteus, bei den iibrigen 
Siugetieren auf der Gelenkskapsel, bedekt von dem oben erwaihnten Muskel. 
Diese Verschiedenheit im Verlaufe der Poplitea kann nur auf die weise erklirt 
werden, dass entweder die den Muskel querenden Stiicke der Poplitea nicht 
homolog oder die beiden Muskeln nicht dieselben sind. Nach meinen bisherigen 
Erfahrungen scheint ersteres wahrscheinlicher zu sein. (Zuckerkandl (’95), p. 
255.) 
