QUESTIONS AND ANSWERS 213 



(b) Inflammation of the covering of a bone. 



(c) Inflammation of the bone-marrow or bone and marrow. 



Give cause, symptoms and treatment of aseptic periostitis. 



Caused by traumatisms acting subcutaneously, such as kicks, 

 blows, treads, and pressure on the interdental space. 



Symptoms : Pain on palpation, lameness, swelling and heat. 

 Treatment: Moist warmth, massage, absorbing agents as cam- 

 phor, iodine ointment or mercurial ointment. 



What is caries? 



A liquefaction necrosis of bone or teeth in which they become 

 softened, discolored and porous. There is usually associated with it 

 a chronic inflammation of the periosteum and surrounding tissues, 

 and an abscess formation which burrows through the soft parts 

 until it opens externally by a sinus or fistula. 



Define fracture. Give the varieties of fracture. 



A fracture is a break or division of the continuity of a bone. 



Varieties : Simple and compound ; complete and incomplete (fis- 

 sure and green-stick) ; transverse, oblique and longitudinal; simple 

 and multiple (comminuted) . 



Define (a) simple fracture, (b) compound, and (c) comminuted frac- 

 ture. 



(a) A fracture of a bone without injury to the skin. 



(b) A fracture of a bone accompanied by a skin wound, so that 

 the bone is exposed and entrance of infection is possible. 



(c) A fracture of a bone in which the bone is broken into small 

 fragments. 



Describe the modes of union of fractures. 



Regeneration of the periosteum and, to a certain extent, of the 

 bone-marrow occurs and a granulation tissue is formed, which subse- 

 quently ossifies. 



What pathologic conditions render bones liable to fracture? 



An abnormal fragility due to senility, rarefying ostitis, osteo- 

 malacia, rachitis, caries, sarcoma and tuberculosis of bone. Diseases 

 of the nervous system, as seen following neurotomy (trophoneurotic 

 bone atrophy) ; anchylosis which restricts the mobility of the joints. 



Describe a method of applying a plaster-of-Paris dressing for fixation 

 in case of fracture. 



After reposition of the broken ends of the bone is effected, the 

 limb is covered with a pad of cotton, over which a flannel bandage 

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