440 OPERATIONS ON THE DIGESTIVE APPAEATUS. 



by the shafts of vehicles with either the blunt or broken ends. 

 The laceration of the diaphragm may occur either with or without 

 involving the fracture of the ribs. Several cases of this kind have 

 been seen and recorded by Professor Barrier. 



(b) The Powerful Contractions of the Expiratory Muscles 

 during Yiolent Muscular Efforts. — It may result from the vio- 

 lent and concentrated action of the abdominal muscles, compress- 

 ing powerfully the intestinal mass, and crowding it against the 

 diaphi-agm, until it destroys its continuity at one or more points, 

 sufficiently to admit of the passage of the abdominal organ into 

 the thoracic cavity. Durand has seen it in a six-months-old colt ; 

 Didry and Fabey have reported cases where the hernia took place 

 during violent efforts in hauling a load, and Franconi met with a 

 case of a similar character to the one referred to in which the rup- 

 ture opened into the oesophagus. Schild has seen it associated 

 with the efforts of parturition. 



(c) Yiolent Action and Pressure upon the Diaphragm by the 

 Organs Situated on its Posterior Face. — The obliquity, forward 

 and downward, of the inferior plane of the abdomen, is shared 

 forward upon the posterior face of the diaphragm by the organs 

 related to it, as the Hver, the stomach and the anterior cm^vatures 

 of the large colon. These are bulky organs, and their united 

 weight being very considerable, the pressure it exerts upon the 

 diaphragm, under any extra impulse would tend directly and nat- 

 urally to the disruption of the weaker muscular fibres of the 

 midriff, and these yielding, the hernia would immediately become 

 developed, and thus we have the generation of this kind of hernia. 

 A sudden fall might easily bring this to pass, in a second or two 

 of time. Bouley has recorded a case in which this accident oc- 

 cured in an animal cast for a surgical operation. Pilton has seen 

 it take place in an animal falling down while butting against a 

 slope of ground. 



Diaphragmatic hernias, like others, are either acute or chronic ; 

 or convertibly, recent and free, or of old standing, with adhesions. 

 The distinctions of hepatocele, splenocele, stomachocele and entero- 

 cele are of but Httle importance, none of these differences being 

 discoverable in the living animal. 



The symptoms of acute hernia of the diaphragm differ, accord- 

 ing to the extent of the laceration of the muscle, and the size of 

 the displaced abdominal mass. There are cases in which the in- 



