Anatomy of the microvasculature of the tibial diaphysis of the adult dog.

UNLABELLED: The microvasculature in the cortex and marrow of the adult canine tibial diaphysis was filled with the silicone elastomer Microfil, the bone was decalcified, and the water was replaced with methylsalicylate to permit three-dimensional visualization of the microvascular arrangements. The tibial nutrient artery was seen to supply the marrow and the cortex via parallel, independent sets of arterioles and terminal capillary beds. No arteriolar or capillary anastomoses were observed linking these separate beds. The major portion of the venous drainage was found to be via small venules through the cortex into periosteal veins. Many small venules draining the medullary capillaries penetrated the cortex, and there were a few larger emissary veins, including the nutrient vein. Because the marrow and cortex have separate capillary beds in parallel, microsphere deposition should be appropriate for estimating the regional blood flows. CLINICAL RELEVANCE: The results of this study should be of concern to surgeons who perform whole diaphyseal bone replacements, as the effluent venous vessels are important in re-establishing the circulation by microsurgical methods.