An enlargement of the floor of the belly caused by the extrusion of a portion of bowel or omentum through the navel opening.
Fig. 114. - Truss for Umbilical Hernia.
In foals it is either congenital or occurs very shortly after birth, in consequence of the umbilicus being still pervious or imperfectly closed. In older animals it is usually provoked by blows, some form of severe exertion, and especially jumping, rearing, and kicking when at play. It seldom occurs after the age of one year.
Umbilical hernia very frequently disappears altogether without being subjected to treatment of any kind. This spontaneous removal of the gut from its pouch is believed to arise in many instances from a natural shortening of the membrane (mesentery) by which the intestines are suspended from the spine. It may also occur as a result of the opening becoming closed, the bowel being thus dislodged from its sac and restored to its proper cavity.
Where these natural means of cure do not come into operation, the early recourse to and frequent application of blisters over the seat of enlargement will often suffice to fill in the aperture and restore the parts to a normal condition, especially if at the same time the patient be put on a spare diet and kept in quiet confinement. It is most important to the success of any treatment that distension of the bowels be avoided, since increase of the pressure from within tends to force them through the opening and prevent its closure.
Trusses are very difficult to keep adjusted in foals, but when this can be done they are very helpful if applied over a pad of tow the day following the application of a blister. The form and adjustment of a suitable truss are shown in fig. 114.
Fig. 115. - Clamp for Umbilical Hernia.
Fig. 116. - Treatment of Umbilical Hernia with a Clamp.
Many foals are successfully operated upon by a simple method of clamping the skin after pushing back the hernia, Before treatment is commenced the animal is prepared for the operation by abstinence from food for twelve hours, and then cast and secured upon his back. By a little careful manipulation the extruded parts are returned, the skin over them is then pinched up into a fold and held in the fingers by an assistant, while a clamp of wood or steel (fig. 115) is placed upon it as close as possible to the abdomen, and tightly compressed and secured in position by string or a screw.
The instrument is allowed to remain, when in the course of ten or twelve days, the inflammatory action excited in the subcutaneous tissue will have closed the opening in the abdominal wall, and the clamp with the dead compressed skin will fall away, leaving behind a dense firm scar. In adjusting the clamp care must be taken not to use so much pressure as to cut the skin or cause its too speedy death, lest it should fall away before the orifice is filled in.
Another method having the same end in view is the introduction of two metal skewers, or strong needles, beneath the skin of the part, cross-ways (fig. 117), after which a ligature is tightly bound round the skin above them, and allowed to remain until the integument and skewers fall away. In performing this operation the greatest care should be observed that the skin and the instruments to be passed through it are thoroughly clean and disinfected, and above all that the sac is completely emptied of its contents before the skewers are introduced.