234 



V. CAGLIOTI, A. ASCENZI AND A. SANTORO 



33-week foetus 



Age 60 

 Arthricic 



Fig. 3. Diagram showing direction of orientation of the 

 collagen fibrils in the articular cartilage of the femoral head 

 (a) of a 33-week stillborn foetus, (b) of a normal adult aged 

 42, (c) of an osteoarthritic subject. 



In normal ageing, by the time middle age is reached 

 the orientation on the surface is still parallel with that 

 surface with a tendency towards preferred orientation 

 away from the ligamentum teres. The outer two 

 thirds or so of the articular cartilage remains un- 

 orientated (figure 3). but there is a tendency for the 

 inner layers of cartilage adjacent to the bone to 

 show definite orientation at right angles to the sur- 

 face. 



In arthritic hips the entire thickness of the carti- 

 lage has its collagen fibrils orientated at right angles 

 to the surface of the bone, with the exception still 

 of the fibrils in the surface layer of the cartilage 

 which remain parallel to the surface till the cartilage 

 has begun to split and wear away. It seems that this 

 change in the direction of the collagen fibrils is 

 most easily explained in terms of tensional forces 

 across the joint which is in agreement with the obser- 

 vation that arthritis first appears in the non-weight 

 bearing areas. 



With regard to the cartilage cells both living and 

 dead cells have been encountered at all ages and in 

 all states of the cartilage, and with the electron 

 microscope it has been so far impossible to establish 

 any relationship between the cartilage cells and the 

 well-being or otherwise of the cartilage. 



References 



In the foetus and newborn child diffraction shows 

 that the whole of the cartilage is unorientated except 

 for the immediate surface layer in which the collagen 

 fibrils lie parallel to the surface. This lack of orienta- 

 tion as demonstrated by x-ray diffraction could be 

 due to one of two causes. Either, as in the present 

 case, because the collagen fibrils themselves are 

 randomly orientated, or as in fibrocartilage, because 

 the bundles of collagen are randomly orientated. 

 It requires the electron microscope to distinguish 

 between these two. 



1. Ekholm, R., Acta Aiiat., Suppl. 15, 1 (1951). 



2. Ekholm, R. and Norback, B., Acta Ortlwpaed. Scand. 



21, 81 (1951). 



3. Harrison, M. H. M., Schajowicz, F., and Trueta, J., 



/. Bone ami Joint Surg. 35 B, 598 (1953). 



4. Ingelmark, B. E., Acta Ortlwpaed. Scand. 20, 144 (1950). 



5. Ingelmark, B. E. and Saaf, J., Acta Ortlwpaed. Scand. 



17, 303 (1948). 



6. Matthews, B. F., Brit. Med. J. 2, 1295 (1952). 



7. — ibid. 2, 660 (1953). 



8. MiJLLER, W., Biologic der Gelenke. Johann Ambrosias 



Barth. Leipzig, 1929. 



9. Trueta, J. and Harrison, M. H. M., /. Bone and Joint 



Surg. 35 B, 442 (1953). 



Correlation of Electron Microscopy with X-Ray Diffraction anci Optical 



Birefringence in the Stu(dy of the Bone 



V. Caglioti, a. Ascenzi and A. Santoro 



Institute of General and Inorganic Chemistry and Institute of Morbid Anatomy, 



University of Rome 



Engstrom and Finean (8, 10, 11), and Carlstrom 

 and Finean (6) demonstrated that in addition to the 

 wide angle x-ray diffraction pattern, bone tissues 

 also give a diffuse low-angle scatter. The same 

 authors assumed that the low-angle scatter could be 

 treated as a particle scatter pertaining to the inor- 

 ganic or mineral fraction. In this way they conclude 



that the particles are rod-shaped, the long axis of 

 rods being aligned in the direction of the longitudinal 

 axis of the bone, and parallel to the collagen fibres. 

 In the intact human bone these particles appear to 

 have a diameter of about 73 A and a length of about 

 210 A. 



Recently Robinson and Watson (15) have criti- 



