DIAGNOSIS OF VENTRAL HERNIA. 501 



exceeds the size of the clenched fist or, at the most, of a man's head 

 but greater dimensions are occasionally reached, as in the case of 

 the mare shown in Fig. 399. 



Differential diagnosis. Recent cases may be mistaken for inflam- 

 matory swelling, abscess or hsematoma in the abdominal wall. In 

 those of old standing the hernial aperture can usually be discovered 

 by palpation, provided accidental inflammatory processes are absent 

 from the affected region. Occasionally the hernial swelling (small 

 intestine) is some distance behind or below the breach in the abdominal 

 wall. The sudden appearance of the swelling and its compressibility 

 must arouse suspicion of a rupture. In any case, caution is required 

 in operative interference, and, in doubtful cases, sharp instruments 

 should not be used before making certain of the absence of hernia. 

 Rectal examination is sometimes useful, and, if needful, the parts 

 can be punctured with a trocar, under antiseptic precautions. 



Particular caution is indicated in presence of colic, which may 

 proceed from incarceration, but in fresh injuries may also be caused 

 by the pain associated with peritonitis ; though the latter is the 

 exception, the former the rule. 



Frequently adhesions form, but strangulation is not at all common 

 and some have denied its occurrence ; but undoubtedly both recent 

 and old ventral hernise do occasionally become strangulated, though the 

 danger is much less than in either umbilical or inguinal hernise. The 

 symptoms are similar in all. The necessary conditions are a small 

 opening and a large sac. The immediate cause may be heavy work, 

 tympanites, colic, or parturition, and it is common experience that 

 the small intestine becomes more readily strangulated than the colon. 

 Small ventral herniae sometimes disappear spontaneously, and even 

 large ones diminish with lapse of time. 



Ventral are thus usually more hopeful than inguinal hernise, 

 though, by their position, they may seriously interfere with the use 

 of harness horses, and are always a danger in the event of the animal 

 suffering from colic or tympanites, or becoming pregnant ; and, for 

 this reason, female animals with ventral hernise should not be used 

 for breeding. 



Treatment is best confined, in recent cases, to counteracting 

 inflammatory symptoms, unless strangulation has occurred. Under 

 favourable circumstances, the hernial contents may be replaced, or 

 further egress prevented by a carefully applied compress ; but it 

 must not be forgotten that any considerable pressure may cause 

 necrosis of the skin and favour prolapse. Old ventral hernias seldom 

 receive treatment, unless they interfere with the animal's work, when 



