DISEASES OF THE THORAX. 473 



DISEASES OF THE THORAX. 



I.-FRACTURES OF THE RIBS— FRACTUR/E COSTARUM. 



Fractures of the ribs are usually produced in the larger domes- 

 ticated animals by external violence, by thrusts from carriage-poles, 

 kicks, falling on uneven hard ground, unskilful casting, and in the 

 case of runaways by collisions with obstructing objects ; in ruminants, 

 from blows with the horns ; and in smaller animals from being run 

 over, treads with the foot, or falling from considerable heights. 

 Contused fractures are most common. Breakage seldom results 

 from excessive muscular action, though Stockfleth has seen fracture 

 of the first ribs produced in horses drawing heavy loads. Fractures 

 of the ribs seem most frequent in swine, but are usually discovered 

 only after death. Charpentier and Lafourcade, from observations 

 in the slaughter-houses, found that 15 per cent, of swine had suffered 

 fractures of the ribs, many of which had completely united. Simple 

 transverse fractures are most common ; but sometimes the fracture 

 is incomplete, the concave surface bending inwards, and the 

 periosteum occasionally remaining uninjured (subperiosteal fracture). 

 Less frequent are compound fractures, involving injury to the skin. 

 In such fractures the pleura and lungs, or the peritoneum and 

 abdominal walls, are sometimes injured. In a case of Grosswend's, 

 a horse's last rib having been fractured, the fragments perforated 

 the omentum and stomach. 



The course taken is determined by the form and variety of the 

 injury. Partial and simple subcutaneous fractures of the anterior 

 ribs usually unite completely without marked symptoms. The 

 great mobility of the posterior ribs interferes, however, with their 

 union ; a callus fibrosus, or pseudoarthrosis forms, but does not 

 impair health, and, indeed, is often only discovered after death. 



Compound fractures, involving perforation of the skin, may lead 

 to pus formation and necrosis of the rib ; but healing, even though 

 complicated and long delayed, occurs. Should the sequestrum not 

 be removed, a costal sinus may, however, develop. 



When the pleura, lung, or peritoneal cavity is involved, the con- 

 sequences are much graver. In penetrating injuries of the thorax, 

 air frequently enters the pleural sac, but is commonly without danger ; 

 for it has been found that air does not contain infective materials 



