Changes

==Description==  

==Description==  

[[Image:hernial sac.jpg|thumb|right|150px|Diagram of a hernial sac (Courtesy of Elspeth Milne)]]

[[Image:hernial sac.jpg|thumb|right|150px|Diagram of a hernial sac (Copyright Elspeth Milne 2007)]]

A hernia is defined as the displacement of an organ through a normal aperture (a '''true hernia''') or pathological aperture ('''false hernia''' or '''rupture''').  The mobile organs of the abdomen are most commonly displaced through apertures in the abdominal wall, diaphragm, inguinal canal or femoral canal.  

A hernia is defined as the displacement of an organ through a normal aperture (a '''true hernia''') or pathological aperture ('''false hernia''' or '''rupture''').  The mobile organs of the abdomen are most commonly displaced through apertures in the abdominal wall, diaphragm, inguinal canal or femoral canal.  

==Types of hernia==

==Types of hernia==

*'''Umbilical hernias''' are congenital and result from a failure of closure of the foetal umbilical canal.  They occur in all of the major domestic species.

*'''Umbilical hernias''' are congenital and result from a failure of closure of the foetal umbilical canal.  They occur in all of the major domestic species.

*'''Diaphragmatic hernias''' may be congenital or, much more commonly, [[Diaphragmatic Rupture|diaphragmatic ruptures]] may occur following blunt abdominal trauma in small animals.  Congenital diaphragmaic hernias are an unusual cause of small intestinal incarceration and strangulation in horses, manifesting as severe colic.  If the septum transversum (the embryonic structure that forms the diaphragm) fails to develop fully, congenital [[Hernia, Peritoneopericardial Diaphragmatic|Peritoneal-Pericardial-Diaphragmatic hernias]] (PPDH) or [[Hernia, Pleuroperitoneal Diaphragmatic|Pleuroperitoneal hernias]] may occur.

*'''Diaphragmatic hernias''' may be congenital or, much more commonly, [[Diaphragmatic Rupture|diaphragmatic ruptures]] may occur following blunt abdominal trauma in small animals.  Congenital diaphragmaic hernias are an unusual cause of small intestinal incarceration and strangulation in horses, manifesting as severe colic.  If the septum transversum (the embryonic structure that forms the diaphragm) fails to develop fully, congenital [[Hernia, Peritoneopericardial Diaphragmatic|Peritoneal-Pericardial-Diaphragmatic hernias]] (PPDH) or [[Hernia, Pleuroperitoneal Diaphragmatic|Pleuroperitoneal hernias]] may occur.

==References==

==References==

[http://w3.vet.cornell.edu/nst/nst.asp?Fun=Image&imgID=22114 Image of congenital umbilical hernia in a pig from Cornell Veterinary Medicine]

[http://w3.vet.cornell.edu/nst/nst.asp?Fun=Image&imgID=22114 Image of congenital umbilical hernia in a pig from Cornell Veterinary Medicine]

[[Category:To_Do_-_James]]

[[Category:To_Do_-_James]][[Category:Intestine_-_Physical_Disturbances]]

[[Category:Peritoneal_Cavity_-_Developmental_Pathology]][[Category:Dog]][[Category:Cat]][[Category:Horse]][[Category:Donkey]][[Category:Cattle]][[Category:Sheep]]

[[Category:Peritoneal_Cavity_-_Developmental_Pathology]][[Category:Dog]][[Category:Cat]][[Category:Horse]][[Category:Donkey]][[Category:Cattle]][[Category:Sheep]]