Diaphragmatocele — Diaphragmatic Hernia — Phrenic Hernia. 369 



buffers of cars, the end of a gate and the gatepost, projecting ends 

 of bars or beams against which they run, kicks by horse or ox, 

 blows by the horns of cattle or tusks of boars. In the smaller 

 animals in addition to the above, blows with' heavy clubs and 

 kicks with heavy boots. In all such cases there is usually a frac- 

 ture of one or more ribs, the sharp broken ends of which are 

 forced into the diaphragm, which they tear when they again 

 spring outward. The same occurs as the result of falls on hard 

 projecting bodies of any kind. 



2nd. Muscular Strain. In heavy draught the fixing of the 

 glottis, ribs and diaphragm and the extreme contraction of the 

 abdominal muscles often lead to extraordinary tension of the mus- 

 cular septum by the mere violence of which, or when there is 

 superadded a sudden shock, (in plunging in harness, or displace- 

 ment of the feet or slipping and falling,) the diaphragm is torn, 

 usually in its tendinous portion, and the abdominal viscus pro- 

 trudes into the chest. If the diaphragm is momentarily relaxed 

 the lesion may take place in the peripheral muscular portion. 

 In still other cases the lesion is at one of the natural openings. The 

 same accident occurs in animals thrown for operation, the 

 abdominal viscera being full, the hind limbs drawn forward so as 

 to further compress the belly, and the muscles being subjected to 

 violent contraction in the efforts to get loose. Violent straining 

 in dystokia is another cause which, however, usually partakes of 

 a sudden shock on the diaphragm when a violent pain sets in. 



3rd. Sudden Shocks on the diaphragm, and pressure by 

 the abdominal organs. In the horse especially the weight of 

 the abdominal viscera is very great and the floor of the abdomen 

 inclines downward and forward so that the whole mass presses 

 with great force against the concave diaphragm. In cattle the 

 great weight of the stomach and liver is especially important and 

 in dog and pig of the liver mainly. In trotting or galoping down 

 hill or jumping from a higher to a lower level, or in slipping back 

 on the fore feet so that the horse falls on the knees or shoulders, 

 this pressure is suddenly greatly enhanced and the tense diaphragm 

 may give way in its tendinous portion or the relaxed organ 

 through its muscular tissue. A similar danger attends on the 

 violent straining which attends on difficult cases of parturition, 

 and even in cases of overloaded stomach and tympany and 

 24 



