62 THE STRUCTURE OF MAN 
in question. This third, or gluteal trochanter, may be ac- 
companied by a more or less extended ridge (cr., Fig. 58) or by a 
pitlike depression. It is found in about 30 per cent of Huropean 
skeletons ;+ in Negroes its occurrence is less frequent, and in the 
Anthropoids it is still rarer. ; 
“ In the Lemuroidea, on the other 
~~ hand, the third trochanter is almost 
Rn) @) always developed. Dollo attributes 
Sage: : . 
ol - NU its gradual disappearance in Man to 
yy" certain modifications which, in the 
course of time, have taken place in 
the gluteus maximus muscle. In the 
Lemuroids this muscle passes direct 
to the femur, and the development of 
a third trochanter is unquestionably 
an outcome of this association; but 
in Man, the gluteus maximus is 
partially inserted into the fascia lata 
investing the superficial parts of the 
limb; and this shifting of its attach- 
ment would appear to have led to an 
Fic. 58.—PROXIMAL HALF OF A accompanying degeneration of the 
LEFT HUMAN FEMUR POSSESSED hae h 
OF THREE TRocHanTERS, Pos- third trochanter. 
BELO ge al Sout In the Anthropoid Apes the 
tc’., greater ; tc’’., lesser; anditc’”., - . f y 1 : 
third or gluteal trochanter. Insertion 0 the § uteus maximus 
into the fascia lata has gone much 
farther than in Man, ze. this muscle has in them deviated 
farther from its original condition [in which we find it in many 
quadrupedal types], and the occurrence of the third trochanter 
is therefore much less frequent. 
The lower part of the leg (fore-leg) has, like the lower part 
of the arm (forearm), but to a far higher degree, undergone 
great modifications in length in the races of mankind. ‘The 
variations of the human tibia, indeed, are greater than those of 
any other bone in the skeleton. Apart altogether from variation 
in length, the term platyknemia is applied to a peculiar condition 
associated with great compression of the tibia. This is found 
in the lower races, accompanied by a strong development of the 
tibialis posticus muscle, and in skeletons belonging to prehistoric 
times. 
1 [Treves has recently called attention to a case in which it could be readily 
detected in the livin gperson (Jour. Anat. and Phys., vol. xxi. p. 325).] 
