568 PROCEEDINQS OF SECTION F. 



counted, however, by the nearly normal condition of the right femur 

 of the same subject. You require to be careful in science : you never 

 know when you will stumble on the tragedy of " a deduction murdered 

 by a fact." 



Tibia. — Here, too, several points have to be considered — especially 

 platycnemia and retroversion of the head of the bone. But little that 

 is definite has been done. 



The subject of platycnemia* demands some remarks. This con- 

 dition has been discussed in detail by Manouvrier, who considers that 

 it is associated with the attainment of maturity. Duckworth {Mor- 

 phology and Anthropology, p. 313, et seq.) discusses the subject at some 

 length. He says, " The condition was undoubtedly common in some 

 prehistoric races of Western Europe and Egypt. In modern times it 

 occurs in a pronounced degree in rickety tibiae and in the tibise of certain 

 ill-fed and badly nourished Australian aboriginal tribes (c/. the des- 

 cription of the " boomerang "-tibia by Messrs. Spencer and Gillen, 

 The Natives of Central Australia). Pruner-Bey attributed all platyc- 

 nemic cases to Rachitis (Rickets)." Then Duckworth goes on to state 

 the views of Broca and of Manouvrier and of Charles, and to criticise 

 them. The lowest index he himself has found, i.e., the greatest amouat 

 of platycnemia, was in a mori-ori skeleton at Cambridge, and amounted 

 to 60. I am able to record an index of 57 in the left tibia of a young 

 subject from the Coorong, in whose skeleton there is no evidence what- 

 soever of rickets or any other disease. In another skeleton the index 

 was 57 . 1 on the right side and 51.3 on the left ; in a third it was 65 . 7 

 on the right and 62.8 on the left. In an odd tibia it was 54.2 ; in 

 another, 57.8. This gives, for six tibiae from one locality, an average 

 of 58. 1, which shows a very much greater degree of platycnemia than in 

 any known race, the nearest being an average of three tibise of the 

 Mori-oris, which amounted to 68. f 



It appears to me that this subject offers a field of fruitful study 

 in connection with the functions of the lower extremity, and on account 

 of the possibility of its yielding racial characters. I have to point out 

 that the ridge that constitutes the condition of platycnemia does not 

 correspond with the oblique line of the tibia, nor with the longitudinal 

 ridge that separates the surfaces of origin of the flexor longus digitorum 

 and tibialis posticus muscles. In one well-marked case the platycnemic 

 ridge passed from its origin — about 2 cm. from the fibular articular 

 surface — -downwards and inwards, as a well-defined continuous border, 

 to the posterior portion of the internal malleolus. The true inner 

 border of the tibia was marked only in the upper half of the shaft. 

 The commonly-accepted view {Quain's Anatomy, Osteology, p. 127 ; 

 Macalister, A Text-hook of Human Anatomy, p. 182) that the condition 

 is due to prominence of the posterior longitudinal ridge is certainly 

 incorrect. The bulk of the growth is sometimes external and sometimes 

 internal to the arterial foramen. 



* This term is an unfortunate one, and gives rise to misunderstanding. It 

 is wrongly defined in Gould's Dictionary of Medicine. 

 f See footnote on p. 569. 



