334 SPECIAL HISTOLOGY. 



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 appearance, in which 

 case partial ossification frequently either precedes or follows. 

 The fibrous ligaments are poorly supplied with vessels, and 

 particularly the elastic ligaments, and in this respect may be 

 arranged with the tendons, whilst the synovial membranes are 

 characterised by the considerable number of their blood- 

 vessels. The above-described synovial folds are especially rich 

 in this respect, as is also the synovial membrane itself, which, 

 every where beneath the epithelium, contains a pretty close 

 plexus of canals, from 0004 — 001 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 endeavoured to find such vessels. With respect to the 

 other parts of the osseous system, the only question can be, as 

 to whether the periosteum and articular capsules possess lym- 

 phatics. In the former, they have not yet been observed, 

 whilst in the latter their existence has been asserted by several 

 authors, Cruveilhier, for example. It must be confessed, how- 

 ever, that it has not been by any means proved that they arise 

 in these structures, at all events it appears to me to be very 

 doubtful, whether the sj^novial membranes themselves contain 

 vessels of this kind, whilst it is perhaps certain that lymphatics 

 do exist in the loose connective tissue surrounding the articular 

 capsules, and between them and the periosteum of the apophy- 

 ses, particularly at the knee. 



§ 99. 



Nerves of the osseous System. — The periosteum is abun- 

 dantly supplied with nerves, the majority of which, however, 

 do not belong properly to it, but to the bone (vid. infra). 

 With respect to the proper periosteal nerves, it appears that 

 their number, on the whole, is not considerable, so that even 



