THE OSSEOUS SYSTEM. 385 



in some places they may be entirely absent, as in the neck of 

 the femur, and beneath certain muscles [glutaeua minimus, 

 peromei, Sec.) ; but there are perhaps but few bones in which 

 they do not exist in one part or another. These nerves lie in 

 the same layer as the vessels, sometimes along the larger 

 branches, sometimes by themselves, arising, at all events in 

 part, from the larger nerves of the bone itself, and are mani- 

 festly distributed over considerable spaces, although their 

 ramifications and anastomoses are scanty. In the larger 

 trunks of these nerves the primitive fibres measure, most 

 generally 0-002 — 000 \!" , though their size gradually lessens, 

 partly owing to actual divisions, which I have seen with the 

 utmost distinctness in the periosteum of the fossa infra-spinata, 

 and iliaca in man, and J. N. Czermak in that of the frontal 

 bone in the Dog ; and in part by a gradual attenuation, to a 

 diameter of 0-0012 — 00016'", many, and perhaps all, ter- 

 minating with free extremities. On the articular ends of 

 many bones, such as those of the elbow, knee, and knuckle- 

 joints, I have noticed the nerves to be more abundant than 

 elsewhere, ramifying and anastomosing in the vascular con- 

 nective tissue covering the periosteum, and following prin- 

 cipally the course of the blood-vessels ; but in these situations, 

 divisions and terminations of the primitive fibres did not come 

 under my observation. 



The nerves of the bone itself, which, with the exception per- 

 haps of the ossicula auditus and sesamoid bones, are univer- 

 sally present, do not exhibit exactly the same conditions in all 

 bones. In the larger cylindrical bones, they penetrate, in 

 company with the nutrient vessels, in the form of one, or 

 where two nutrient foramina exist, of two, pretty considerable 

 trunks (measuring as much as 0-16'") visible to the naked 

 eye, directly into the medullary cavity, and are there distri- 

 buted in the medulla, following the course of the vessels, 

 though not always in apposition with them, towards the 

 apophyses, and forming multifarious ramifications, but, at least as 

 far as I have seen, only few anastomoses. In the second 

 place, all these bones also present, in the apophyses, numerous 

 finer nerves, accompanying the equally numerous blood-vessels 

 directly into the spongy substance, and ramifying in the 

 medulla ; and thirdly, extremely delicate filaments are sent 



