S-2 



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 European 

 skeletons ; 1 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 

 always developed. Dollo attributes 

 its gradual disappearance in Man to / 

 certain modifications which, in the 

 course of time, have taken place in 

 the glutens 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 



FIG. 58. PROXIMAL HALF OF A accompanying degeneration of the 

 LEFT HUMAN FEMUR POSSESSED , . , . 



OF THREE TROCHANTERS, Pos- third trochanter. 

 TERIOR ASPECT. In the Anthropoid Apes the 



ur, 



into the fascia lata has gone much , 

 farther than in Man, i.e. this muscle has in them deviated I 

 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).] 



