ANTHROPOMETRY 121 



Long Bones: The form of the shaft of the long bones is best differenti- 

 ated at or near the middle of the bones, in adult individuals. 



Variation in these shapes is greatest in the Whites. There are 

 considerable racial and other group differences in the relative fre- 

 quency of the different types of the shaft of the various bones; no one 

 type, however, occurs exclusively or is completely absent in any of 

 the human groups now existing. Some of the shapes are common to 

 the anthropoid apes, and others occur far back in the animal kingdom. 



The bones of the lower extremity show more numerous and better 

 defined differentiations of form than those of the upper extremity. 

 Of the individual long bones, the fibula presents the greatest variety 

 of shapes; then follow in the order named, the tibia, femur, humerus, 

 ulna, and radius. 



Perfect representations of the various types of each bone are found 

 whenever large collections are examined, but the less perfect and 

 less clearly distinguishable types are always more common. Besides 

 there is always a considerable percentage of bones which present 

 intermediary or indefinite, and a small proportion which show com- 

 bined forms. 



The form of shaft common to all the long bones in man is the pris- 

 matic (No. 1). The outline of the cross-section of a shaft of this type 

 approaches the equilateral triangle. This type is also common in 

 apes, and more or less modified in lower mammals. The base of the 

 prism is formed in the tibia, fibula, and humerus by the posterior 

 surface; in the femur by the anterior surface; in the ulna by the in- 

 ternal, and in the radius by the external surface of the bone. In 

 whites this type of shaft is most frequent in the humerus and tibia. 

 In the fibula it is more or less modified by the narrow anterior surface 

 of the bone. 



The nearest modifications of type 1 are types of shaft Nos. 2 and 4. 

 Type 2 occurs principally in the tibia, fibula and humerus, and is 

 characterized by the obliquity of the posterior surface of the bone. 

 The outline of the cross-section is a lateral triangle, a half lozenge 

 (more or less). Type 4 occurs in all the long bones, and is charac- 



chez Thomme et chez les singes. Bull. Soc. d'Anthrop. Paris, 1887, Se*r. 3, X, 128. 

 Me"moire BUT la platycne*mie chez Phomme et chez les anthropoids. M 6m. & Bull. 

 Soc. d'Anthrop. Paris, 1888, S6r. 2, III, 469. fitude sur les variations morphologiques 

 du corps de fe"mur dans 1'espece humaine. Bull. Soc. d'Anthrop. Paris, 1893, S4r. 4, 

 IV, 111; Rev. d'ficole d'Anthrop. Paris, 1893, III, 389. And Graves (Wm. W.) The 

 scaphoid scapula. Med. Record, May 21, 1910; Wien. klin. Woch., 1912, XXV, No. 

 6; J. Cutan. Dis., etc., April, 1913; and others on same subject. 



