522 DIAGNOSIS AND PROGNOSIS OF HERNIA. 



character may also be due to strangulation or other causes, like 

 excessive distension of the protruded portion of intestine by gas or 

 hard masses of faeces. 



Diagnosis. A hernia is seldom difficult to recognise, provided 

 it be reducible. In such case it has the following characteristics : — ■ 



(a) It is free from inflammatory symptoms (especially pain), 

 is soft, elastic, and compressible, that is, it may be diminished by 

 pressure. 



(b) It varies in size from time to time ; coughing or severe exertion 

 increase abdominal pressure and render it larger ; but it decreases 

 when intra-abdominal pressure again falls. 



(c) It is reducible, that is, the swelling may completely disappear 

 on pressure, or on placing the animal in a suitable position, but it 

 returns on removal of pressure or alteration of position. Irreduci- 

 bility may be suspected when the hernial swelling undergoes little 

 or no alteration in size from day to day. 



Diagnosis only becomes absolute when the hernial opening is 

 discovered. It can generally be felt by thrusting a finger into the 

 depth of the sac, especially after reducing the hernia. Examination 

 per anum is sometimes useful in horses and oxen ; the hernial ring 

 and the contained bowel may be felt ; by traction on the bowel 

 the hernia can sometimes be reduced. Exploratory puncture may 

 also be resorted to in otherwise doubtful cases. Some care is required 

 to differentiate hernia from abscess or haematoma, an error which 

 might have grave consequences, as pointed out in referring to bruises 

 of the abdomen. 



Prognosis. Reducible hernia is not a fatal condition, but im- 

 mediately strangulation occurs it becomes exceedingly dangerous. 

 Prognosis chiefly depends on the probability of strangulation, a 

 factor which will be considered under the various herniae. The 

 smaller the hernial aperture compared with the size of the sac, the 

 greater the danger of strangulation. Small intestine becomes more 

 easily strangulated than colon or omentum. The size of the aperture, 

 and the use to which the animal is put, must be considered, whilst 

 it should be remembered that strangulation occurs more easily in 

 working-horses, and that large herniae may interfere with usefulness. 



Many herniae, and especially umbilical and inguinal herniae in 

 young animals, disappear without treatment, and others may last 

 the animal's whole life without interfering with its use. 



Irreducible herniae are more dangerous than reducible, recent 

 than old, and intestinal than omental, because in each case the former 

 are more likely to become incarcerated than the latter. 



