. Principles of human physiology : with their chief applications to pathology, hygiene, and forensic medicine : especially designed for the use of students. ies of tortuous canals of remarkable size andvery characteristic appearance. These are welldescribed by Breschet in his elaborate work on thevenous system. These canals run, for the mostpart, in the cancellated structure of the bones, andare lined by a more or less complete layer of com-pact tissue, which itself often contains minuteHaversian canals. The veins they contain dis- lonsitudinal section of the com- , , , . , .1 /- pact tissue o
. Principles of human physiology : with their chief applications to pathology, hygiene, and forensic medicine : especially designed for the use of students. ies of tortuous canals of remarkable size andvery characteristic appearance. These are welldescribed by Breschet in his elaborate work on thevenous system. These canals run, for the mostpart, in the cancellated structure of the bones, andare lined by a more or less complete layer of com-pact tissue, which itself often contains minuteHaversian canals. The veins they contain dis- lonsitudinal section of the com- , , , . , .1 /- pact tissue of the shaft of one of charge themselves separately on the surface.— the iong bones:-a. Arterial ca-The Haversian canals vary in diameter from ?5V0 nal *• Venous canal- c- Dila-t0 the 3J-0 of an inch, or more, the average being talion of anothervenous canal-about ji ,. Their ordinary distance from one another is about T|p- of aninch. They may be regarded as involutions of the surface of the bone forthe purpose of allowing vessels to come into contact with it in greater abun-dance. It is evident that the cancelli, and even the great medullary canal. Haversian canals, seen on 470 OF NUTRITION. Fig. 55, h. itself, are likewise involutions of the osseous surface, though for a partlydifferent end. These larger and more irregular cavities in bone may beconsidered as a dilated form of Haversian canals. They contain vesselsnot only for the nutrition of the thin osseous material forming their walls,but also for the supply of the fat enclosed within them. Nerves of Bone.—The skill of anatomists has hitherto failed to demon-strate the presence of nerves in the interior of bones. Some nerves passthrough bones, but no supply strictly to the osseous matter has yet beenproved. Yet there is little doubt that the vascular surface of bones is fur-nished with nerves: the painfulness of many affections of the periosteum,and of the medullary membrane, seems to place this beyond dispute. Develo
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Keywords: ., bookcentury1800, bookdecade1840, bookpubli, booksubjectphysiology
