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| | ==Positional Changes/ Displacements== | | ==Positional Changes/ Displacements== |
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| − | ===Hernia=== | + | ===[[Hernia]]=== |
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| − | * A hernia is defined as the displacement of the [[Small Intestine - Anatomy & Physiology|small intestine]] through a normal or pathologic foramina.
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| − | ** Occasionally, the [[Large Intestine - Anatomy & Physiology|large intestine]] is involved.
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| − | ====Pathogenesis====
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| − |
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| − | * Associated with trauma or the weakening of tissues.
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| − | ** For example,
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| − | *** Old age
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| − | *** Pregnancy
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| − | *** Straining
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| − | *** Wound dehiscence.
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| − | * Most hernias are external[[Image:hernial sac.jpg|thumb|right|150px|Diagram of a hernial sac (Courtesy of Elspeth Milne)]]
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| − | ** Contents pass through a hernial ring in the abdominal wall.
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| − | ** Are covered with parietal peritoneum, soft tissue and skin.
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| − | *** A hernial sac.
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| − |
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| − | ====Sequelae====
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| − |
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| − | * The sequelae depend on whether the hernia is reducible, or is an incarceration.
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| − |
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| − | =====Reducible hernia=====
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| − |
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| − | * The hernial contents are freely moveable.
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| − | * There are NO sequelae.
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| − |
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| − |
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| − | =====Incarceration=====
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| − |
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| − | * The [[Small Intestine - Anatomy & Physiology|small intestine]] contents are trapped.
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| − | ** The hernia is non-reducible.
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| − | * Venous drainage is obstruced.
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| − | ** Oedema
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| − | ** Congestion
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| − | * Adhesions form between the contents and the sac.
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| − | * Accumulated gas/ ingesta distends the herniated viscus.
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| − | * Obstruction of lumen leads to
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| − | ** Rupture
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| − | ** Peritonitis
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| − | ** Death.
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| − |
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| − | ====Types of hernia====
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| − |
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| − | * '''Umbilical''' - usually congenital.
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| − | * '''Diaphragmatic''' - common following road traffic accidents in the dog and cat.
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| − | * '''Inguinal/scrotal''' - may be:
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| − | ** Congenital
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| − | ** Acquired
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| − | *** E.g. post castration of stallion
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| − | * '''Perineal''' - old male dogs with prostate enlargement.
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| − | * '''Ventral''' -wound site breakdown, old mares
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| − | * '''Omental/mesenteric''' - internal hernias.
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| − | [[Image:volvulus.jpg|thumb|right|150px|Volvulus (Courtesy of Bristol BioMed Image Archive)]]
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| | ===Volvulus=== | | ===Volvulus=== |