104 N. E. Shavc 



Table 3. Haemodynamic constants for rat femoral tissues 



Vols ml "o 



Circulatiou 



Vpjocitv 



Whole T,T,r. Whole -„-„„ :„ ^„^^ (1 C. T.) 



ood liloofl 



EBC in sees 



Inferior mctaphvsis . 22.7 9.9 4.32 1.874 11.4 U.U877 



Marrow 12.8 5.5 3.66 1.587 17.3 U.U578 



Superior mctaphvsis 12.3 5.4 2.77 1.203 13.4 0.0746 



Cortex 8.0 3.5 2.16 0.937 16.1 0.0621 



Inferior epiphysis . 6.7 2.9 2.59 1.124 23.3 0.0429 



Table 4. Relative haemodynamic data (inferior metaphysis = 100''lo) 



The investigation has yielded a comprehensive set of haemodynamic data for the 

 femur of the 140 gm rat under ether anaesthesia. Attention is drawn to the following: 



1. Flow, volume, and velocity of red cells are not necessarily correlated. Pre- 

 sumably haematocrit values differ considerably from tissue to tissue within bone. 



2. The 3 : 1 predominance of flow in the "growing" metaphysis over that of the 

 adjacent epiphysis is in striking contrast to recent and opposite opinion. 



3. The highest flow is in the growing metaphysis and is roughly double that in 

 the non-growing metaphysis. This flow-growth correlation suggests that red cell flow 

 in the osseous circulation is intimately related to the amount of protein synthesis and 

 calcification occurring in the parts of a long bone, and that these have unequal meta- 

 bolic and bone turnover rates. It seems likely that the role of the red cells is not only 

 respiratory. Red cell potassium and enzyme systems may play an important role in 

 the regulation of calcification. 



Acknowledgement 

 This work has been supported by the Medical Research Council of Great Britain. 

 My thanks are also due to Miss Latifa Wafaquani for her skilled technical assistance 

 throughout all phases of this investigation. 



The Influence of Muscle Blood-flow on the Circulation in Bones 



N. E. Shaw 

 Institute of Orthopaedies, London, England 



Heald (1951) and Cecchi and Fiumicelli (1952) drew attention to the impor- 

 tance of the osseomuscular circulation. Examination of bone and muscle blood-flow 

 using the heated thermocouple technique (Shaw, 1963) showed that studies could be 



