26 Size of Articular Surfaces of Long Bones 



vidual cases of large and small bones did not give any encouragement to 

 undertake the labor of elaborate tabulation. 



We come now to the ver}^ important feature of this series of observa- 

 tions that the measurements were made on bones with the articular 

 cartilage not only in place, but not dried. As above mentioned, this is 

 the proper method, as it shows the parts as they are in life, giving the 

 true size of the joints; but there is the serious consideration that most 

 observations are made on dried bones, so that one needs to know what 

 allowance is to be made for the absence of the cartilage. What compli- 

 cates the matter is that the conditions for the humerus and for the femur 

 are not the same. In measuring the practically globular head of the 

 femur, the greatest diameter passes through the centre of the sphere and 

 traverses the whole thickness of the cartilage on both sides of the head. 

 With the humerus the conditions are very different. Both the long and 

 the short diameter, especially the former, run through the bone just at 

 the insertion of the shaft into the head, that is, at the border of the 

 articular cartilage which narrows around the margin of the head so as 

 to be extremely thin. I have been at great trouble to find a method 

 of determining how much to allow for the cartilage and can find none 

 that is satisfactory. I think that from 2 mm. to 3 mm. should be allowed 

 for the femur, and that .5 or 1 mm. is enough for the humerus. 



Wlien the work was far advanced I regretted that I had contented 

 myself with measuring only the heads instead of taking the length and 

 perhaps the thickness of the bones. Although as a practical anatomist 

 I know that no one would think of determining the sex of either of these 

 bones by its length, I felt that it would be difficult to answer anyone 

 who might ask how I could be certain that there is a greater discrepancy 

 between the articular heads of the bones than between their lengths. I 

 had recourse to Dr. Hrdlicka of the National Museum of Washington, 

 who came to my rescue with measurements of bones of 200 white adults, 

 100 of each sex, made by him at the Medical Department of Colum- 

 bia University of New York. The sources from which these bones came 

 are perhaps a little more diverse than those that lead to Boston, but not, 

 ] believe, very much so. I have already shown that the dissecting room 

 material in Boston does not in the least represent any single race.' That 

 from New York is only somewhat more heterogenous. In short this 

 collection of measurements of the length is, failing that of the bones 

 on which the joints were measured, as good as could be expected. It is 

 quite good enough for the very general conclusions I shall draw, I wish 

 to express my deep obligations to Dr. Hrdlicka for his kind generosity 

 in this matter, by which I am enabled to compare with this series of meas- 



