262 Annals of the South African Museum. 



The lower the index from the upper part of the shaft of the hone 

 the greater the degree of flattening, to which the name platymeria is 

 given. Manouvrier regards this as due to the extension of the area 

 of attachment of the quadriceps extensor cruris muscle when in 

 constant and powerful action. Not so much as an extension of the 

 leg but in holding the knee firm while the trunk is extended on the 

 lower limb, as in climbing. In this action the gluteus maximus plays 

 an important role, and its attachment to the bone being at this level 

 may also practically assist in widening the femoral shaft. The con- 

 dition is common among mountaineers ; Duckworth (" Morphology 

 and Anthropology," p. 317 et seq.) throws some doubt on this 

 explanation, but shows that none more credible has as yet been 

 brought forward. 



The average index for the upper region of the femur in the Bush- 

 men skeletons examined is 80-3. In average recent European femora 

 the index is 86, while an extremely platymeric femur of prehistoric 

 age gave an index of 56. 



The diameters at the middle of the shaft show the degree of 

 projection of the linea aspera, a condition known when marked as 

 pilastering. This is due to the development of the attached muscles, 

 or alternatively to the throwing out of bone to resist bending under 

 the weight of the body, such as occurs in rickets. The higher the 

 index the more the pilastering. The average index in the Bush 

 skeletons is 128-2. 



Contrast : — 



Negroes (20) 105•8^ 



Modern French (15) 1092 [ 



Topinard. 

 Kickety Subjects (2) Ill- 



New Caledonians (13) 127-6 I 



This shows a high degree of pilastering among the Bushmen to a 

 degree which would appear to exclude rickets as a cause. 



The transverse measurements of the tibia are taken at the level of 

 the nutrient foramen. 



Transverse diameter x 100 ^ , 



: ^. 7 — = Index. 



Antero-postenor diameter 



A low index shows lateral flattening of the tibial shaft, the area of 

 attachment of the tibialis posticus muscle in extreme cases standing 

 out as a flange. This condition is frequently associated with rickets. 



