302 SPECIAL HISTOLOGY. 



In the short bones, the bloodvessels present pretty nearly the same 

 conditions as they do in the apophyses of the long bones ; the arteries 

 and veins of larger and smaller size entering and quitting the bone at 

 numerous points on the surface, and sometimes, as in the posterior 

 aspect of the bodies of the vertebra?, in very large trunks, the vence 

 basi-vertebrales of Breschet, furnishing a capillary plexus to the 

 medulla, arid also penetrating into the few Haversian canals of these 

 bones. 



In the jto bones, such as the scapula and os innominatum, there are 

 distinct nutritious foramina for the larger arteries and veins ; the com- 

 pact substance receiving finer vessels from the periosteum, and the 

 spongy substance being supplied by numerous and even large vessels, 

 as in the neighborhood of the articular cavities. In the flat cranial 

 bones, the arteries, for the most part, enter both the cortical and spongy 

 substance from without, on both surfaces, presenting the usual conditions, 

 whilst the venae diploeticce, as they are termed, have only their extremi- 

 ties free in the medulla, as in other bones, their trunks, and larger and 

 smaller branches running independently and generally unassociated 

 with medullary substance in large, arborescent, special channels, the so- 

 termed "canals of Breschet," which open at determinate points with 

 large apertures (emissaria Santorini), and communicate freely with the 

 veins of the dura mater, with respect to which relations, however, works 

 on special anatomy must be consulted. The size and number of the 

 veins in the cranial bones, is, moreover, extremely variable, and they 

 are constantly becoming obliterated, particularly in old age, concomi- 

 tantly with the frequent diminution of the diploe, on which account also 

 the venous canals and their openings (emissaria) are of such variable 

 dimensions. 



The articular and other cartilages of the osseous system, even the 

 fibro-cartilages, in the adult, normally contain no vessels at all, except 

 those of the perichondrium, which however in this respect is far inferior 

 to the periosteum. But it may happen, that as in the costal cartilages 

 in the middle period of life and afterwards, vessels make their appear- 

 ance, in which case partial ossification frequently either precedes or 

 follows. The fibrous ligaments are poorly supplied with vessels, and par- 

 ticularly the elastic ligaments, and in this respect may be arranged with 

 the tendons, whilst the synovial membranes are characterized by the 

 considerable number of their bloodvessels. The above described synovial 

 folds are especially rich in this respect, as is also the synovial membrane 

 itself, which, everywhere beneath the epithelium, contains a pretty close 

 plexus of canals, from 0-004-0-01 of a line in diameter. 



B. Lymphatics in bone, have been described by some older and more 

 recent authors (vid. Mikrosk. " Anat.," II. 1, 336), but their existence 

 is still not the less doubtful, and I have in vain endeavored to find such 



