APPLIED ANATOMY 47 



of the diaphysis of a long bone, and here extensive necrosis of the affected portion takes place, 

 and the condition goes by the name of acute infective periostitis. Where this occurs the shaft of 

 the bone dies very rapidly, especially if the singly nutrient artery be thrombosed at the same time. 

 The pus which has formed beneath the periosteum is set free by timely excision, or burrows to 

 the surface; the periosteum then falls back on the necrosed diaphysis and rapidly forms a layer 

 of new periostea! bone, surrounding the sequestrum. This layer is called the involucrum 

 and the openings in it through which the pus escapes the cloacce. When the inflammatory 

 process affects mainly the medullary canal, the condition is spoken of as osteomyelitis, and the 

 two conditions very frequently co-exist, and then go by the name of acute infective necrosis of 

 bone or acute diaphysitis. When the medullary cavity is filled with pus, septic thrombosis i of 

 the veins in the Haversjan canals takes place, and there is a very great danger of septic emboli 

 being separated and carried into the general circulation, thus setting up a fatal pyemia. In 

 fact, pyemia is more frequently due to septic bone conditions than to any other cause. 



In the preantiseptic days pyemia frequently resulted from amputations, when the medullary 

 canal of a long bone was opened by the saw cut. Osteomyelitis ensued, and if the patient sur- 

 vived, a tubular sequestrum of the divided shaft subsequently separated. 



A proper understanding of the epiphyses is of the utmost possible importance to the student, 

 and greatly simplifies many of the problems in the pathology of bone disease. 



Speaking generally, the long bones have at either end an epiphysis from the cartilage of which 

 growth occurs, and hence the shaft of the bone increases in length at both ends. In every case, 

 however, one epiphysis is the more active, and also continues in its activity for a longer time. 

 This actively growing epiphysis is always the one from which the nutrient foramen in the diaphy- 

 sis is directed, and it unites to the shaft at a later date. It follows, therefore, that the increase 

 in length of a long bone is largely dependent on the epiphysis, and hence anything which inter- 

 feres with the growth from this epiphyseal line at any time prior to the union of the epiphysis 

 with the .shaft must result in a cessation of growth in length of that bone. Thus, when dealing 

 with disease in the neighborhood of this actively growing epiphysis very great care should be 

 taken not to excise or destroy its line of union with the shaft. These epiphyses are particularly 

 prone to become the seat of tuberculous, di.sea.se, which especially tends to attack the soft, highly 

 vfljgr-iilar canrellniis tissue. 



Again, tl-yfi actively growing SlliplliYfiEi 1 ^ ^' n ^ i^-^j^^j^u^uiLrf} l n g bone ^hj^Jjj^in the vast 

 majority of cases affected by tjimnr growth in bone, whether it be innocent or malignant, the 

 former (viz., j^igaiiia) usually app^arm^ about pnl-xrtyj anH the latter (viz.. .sarcoma) usually 

 toward the end of the ac.tive. period oi.e^jpby seal grow tlv. 



~~ Epiphyseal growth, moreover, has to be considered by the surgeon when he is about to ampu- 

 tate in a child. If the amputation is being performed through a bone, the actively growing 

 epiphysis of which is at the upper end, and which will continue to grow for many years (i. e., 

 humerus and tibia), it will be necessary to make allowance for this and to cut the flaps long; as 

 otherwise, owing to continued growth, the sawed end of the bone will ultimately project through 

 the stump, and a condition known as "conical stump" will result. This requires removal of a 

 further portion of the bona 



An inflammatory condition termed acute epipJnjsitis also occurs, although it is not so frequent 

 as the acute infective conditions of the diaphysis, owing to the freer blood supply of the epiphysis; 

 in late years it has been shown that acute epiphysitis in children is very frequently the result of 

 a pneumococcal infection, and it may pass on to complete separation of the epiphysis. In this 

 connection it is worthy of note that some of the epiphyseal lines lie entirely within the capsules 

 of their corresponding joints, in other cases entirely without the capsules; and it must follow 

 that in the former case epiphyseal disease, acute or chronic, becomes, ipso facto, practically 

 synonymous with disease of that joint. The best examples of intracapsular epiphyses are those 

 of the head of the femur and the head of the hunierus, and the vast majority of all cases of 

 ^uberculpus djsease_oj_.the hip starts as a tuberculous epiphysitis K/Mit tk intrgpapgnlar 

 nf fVvo fonniii.. again, cases~o? acute septic arthritis of the shoulder- or hip-joint 



generally have their origins in these intracapsular epiphyseal lines, and often result in separa- 

 tion of the affected epiphysis. The other class, or extracapsular epiphysitis, when diseased, do 

 not tend to involve the neighboring joint so readily ; and it should be the surgeon's duty to keep 

 the disease from involving the joint. For example, the trochanteric epiphysis of the femur is 

 extracapsular as regards the hip-joint, and the epiphyseal line of the head of the tibia is well 

 below the level of the knee-joint, and should a chronic tuberculous abscess form in the latter 

 situation, it should be attacked from the outside before it has time to spread up and involve the 

 cartilage of the head of the tibia. It is, therefore, of great surgical interest to note in every case 

 the relations which the various epiphyseal lines bear to their respective joint capsules. 



A knowledge of the exact periods when the epiphyses become joined to the shaft is often of 



great importance in medicolegal inquiries. It also aids the surgeon in the diagnosis of many 



of the injuries to which the joints are liable; for it not infrequently happens, on the application 



r of severe force to a joint, that the epiphysis becomes separated from the shaft, and such injuries 



may be mistaken for fracture or dislocation. 



