CHAPTER 47 



The flow of blood through bones and joints 



WALTER S. ROOT Department of Physiology, College of Physicians and Surgeons, New York City 



CHAPTER CONTENTS 



Bones 



Long Bones 



Vertebrae 



Flat Bones 



Nerve Supply of Bone 



Blood Flow in Bone 



Oxygen in the Blood of Bones 



Intramedullary Pressure 



Temperature of Bone Marrow 

 Joints 



The Blood Supply 



The Nerve Supply 



Blood Flow Through Joints 



Nervous Control of Joint Blood Vessels 



bone must not be thought of as an inert substance, 

 but rather as one of the highly specialized tissues of 

 the body, consisting of active cells which respond 

 promptly to physiological demands upon the skeletal 

 and hematopoietic systems. The cells are sensitive to 

 nutritional and functional processes, and differ in 

 their reactions from those of other tissues only because 

 of the rigidity and stability of the intercellular de- 

 posits of mineral salts. 



Contrary to general belief, bone is a relatively 

 vascular tissue (68). This concept is borne out by the 

 rapidity with which substances injected into bone 

 marrow appear in the general circulation (105, 106). 

 Large infusions can be administered in a short time 

 (4), and this route of giving fluid has been useful in 

 dealing with infants (43) and in treating patients in 

 conditions of hemorrhage and shock (101). 



BONES 



The anatomical features of the vascular system in 

 bones are classified as long bones, flat bones, or 

 vertebrae. 



Long Bones 



Most studies of the long bones have been made 

 upon the femur or the tibia-fibula. The long bones 

 receive blood from three sources: a) the nutrient 

 artery or arteries entering the bone in the shaft, b) 

 blood vessels entering the ends of the bone, and c) 

 blood vessels penetrating the periosteum (fig. 1). 



Radiological observations in which the arteries are 

 injected with radiopaque substances show that the 

 principal nutrient artery of the femur traverses the 

 cortex inclined toward the knee (16). No branches 

 are given to the cortex in the nutrient canal. On 

 entering the medulla, the artery divides into ascend- 

 ing and descending limbs which, with few subdivi- 

 sions, pass to either end of the bone. In general, larger 

 arteries are visualized as sharply defined and tortuous 

 channels in the proximo-distal axis, and are com- 

 paratively few in number. 



Medullary arteries can be traced to the meta- 

 physeal region where they break up into numerous 

 fine vessels which join across the line of union at the 

 epiphyseo-metaphyseal synostosis with others derived 

 from the epiphyseal arteries (fig. 2). Arterial twigs 

 from the main medullary arteries can be seen to pass 

 more or less transversely toward the endosteal aspect 

 of the compactum where they recurve and course for 

 a short distance in the peripheral medullary zone. 

 Here they anastomose with one another, and give rise 

 to fine vessels which pierce the endosteal face of the 

 compactum and arborize irregularly in the inner 

 cortical zone (16). 



There has been some difference of opinion con- 

 cerning the vascular supply to the metaphyseal re- 

 gion. Thus, Weinmann & Sicher (111) state that the 

 nutrient artery supplies the central part of the meta- 

 physis, its more peripheral parts being fed by meta- 

 physeal arteries derived from the periosteum. On the 



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