Hoyme and Bass] SKELETAL REMAINS 375 



occasionally extending to the medullary cavity. Occasionally a su- 

 perficial area of slightly increased density, possibly of periosteal 

 origin, appears to overlay the cortical bone. These areas of de- 

 creased density are usually quite distinct from the normal cortical 

 bone; their surfaces are usually covered with fairly fine vascular 

 lines, running parallel to the long axis of the bone. Except for the 

 immediate vicinity of the swelling, the bone — and the remainder of 

 the skeleton — appears normal in texture, shape, and density. In the 

 fourth type, considerably larger areas of bone are involved, and the 

 changes are more obvious. The bones most frequently affected are 

 the tibiae, the lower ends of the femora, and the distal ends of the 

 radii and ulnae, and usually both right and left limbs are affected 

 equally. The whole tibial shaft appears swollen and bowed, and 

 seems unusually light in weight. Radiologically, the bone appears 

 to be of uniformly decreased density, but of increased thickness ; the 

 width of the medullary cavity is about as in normal bone. Broken 

 surfaces of the bone appear porous, as if the Haversian canals had 

 been enlarged in diameter; and the surface of the bone generally 

 appears to be smooth but covered with fuie pits or lines. Except 

 for sites of muscular attachment, there are no roughened areas, nor 

 are there signs of periostitis, fistulae, or other indications of infection. 



In each of these categories except the first, one finds various degrees 

 of inflammation from mild to severe, and slight textural differences 

 suggesting stages of involvement from early to nearly healed. This 

 in itself suggests that types 2, 3, and 4, represent distinct entities, un- 

 related to each other. The first category is the most difficult to inter- 

 pret. It may represent simply a normal variation; or a relatively 

 mmor injury, such as a severe bruise, which irritated the periosteum, 

 resulting in a temporary increase in blood supply, but which would 

 normally heal without further complication ; or it might be an early 

 stage of one of the other types. The second type, the obvious infec- 

 tions, are relatively easy to identify by localized, but somewhat un- 

 even, bone reaction, evidence of suppuration, and limited skeletal in- 

 volvement. Only if infection spread systemically to other bones 

 would there be any possibility of confusing these injuries with inflam- 

 matory changes of other origin ; such cases would have to be evaluated 

 on the basis of additional evidence. 



The third type, the localized ellipsoidal swellings, seem to represent 

 reactions to injuries, because they are circumscribed in area and ap- 

 pear to have originated on the surface of the bone. Their location in 

 the skeleton supports this interpretation: They appear only on the 

 long bones, and occasionally on the face. The majority appear in the 

 tibia, particularly on the anterior and medial surfaces of this bone; 



