Internal hernias occur when there is protrusion of an internal organ into a retroperitoneal fossa or a

foramen In anatomy and osteology, a foramen (; : foramina, or foramens ; ) is an opening or enclosed gap within the dense connective tissue (bones and deep fasciae) of extant and extinct amniote animals, typically to allow passage of nerves, artery, ...

(congenital or acquired) in the

abdominal cavity The abdominal cavity is a large body cavity in humans and many other animals that contain Organ (anatomy), organs. It is a part of the abdominopelvic cavity. It is located below the thoracic cavity, and above the pelvic cavity. Its dome-shaped roo ...

. If a loop of bowel passes through the mesenteric defect, that loop is at risk for

incarceration Imprisonment or incarceration is the restraint of a person's liberty for any cause whatsoever, whether by authority of the government, or by a person acting without such authority. In the latter case it is considered " false imprisonment". Impri ...

strangulation Strangling or strangulation is compression of the neck that may lead to unconsciousness or death by causing an increasingly hypoxic state in the brain by restricting the flow of oxygen through the trachea. Fatal strangulation typically occurs ...

, or for becoming the lead point of a small bowel obstruction. Internal hernias can also trap

adipose tissue Adipose tissue (also known as body fat or simply fat) is a loose connective tissue composed mostly of adipocytes. It also contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, Blood vessel, vascular endothel ...

(fat) and nerves. Unlike more common forms of hernias, the trapped tissue protrudes inward, rather than outward. Mesenteric defects commonly occur in trauma, such as gunshot wounds to the abdomen. In trauma victims, the defect is usually closed, sometimes with resection of the associated bowel, which may have lost its blood supply. Also mesenteric defects are intentionally created in the Roux-en-Y gastric bypass procedure, being classically known as a Petersen's hernia. The mesenteric defect in such cases, called ''Petersen's defect'', is located between the transverse colon and the mesentery of the alimentary limb (the segment of the jejunum from the jejunojejunostomy until the connection with the proximal segment of the stomach) at the level of the jejunojejunostomy. Internal hernias are difficult to identify in women, and misdiagnosis with

endometriosis Endometriosis is a disease in which Tissue (biology), tissue similar to the endometrium, the lining of the uterus, grows in other places in the body, outside the uterus. It occurs in women and a limited number of other female mammals. Endomet ...

or idiopathic

chronic pelvic pain Pelvic pain is pain in the area of the pelvis. Acute pain is more common than chronic pain. If the pain lasts for more than six months, it is deemed to be chronic pelvic pain. It can affect both the male and female pelvis. Common causes in include ...

is very common. One cause of misdiagnosis that when the woman lies down flat on an examination table, all of the

medical sign Signs and symptoms are diagnostic indications of an illness, injury, or condition. Signs are objective and externally observable; symptoms are a person's reported subjective experiences. A sign for example may be a higher or lower temperature ...

s of the hernia disappear. The hernia can typically only be detected when symptoms are present, so diagnosis requires positioning the woman's body in a way that provokes symptoms. Both internal hernias and

umbilical hernia An umbilical hernia is a health condition where the abdominal wall behind the navel is damaged. It may cause the navel to bulge outwards—the bulge consisting of abdominal fat from the greater omentum or occasionally parts of the small intestine. ...

s are more common in women than men.

References

{{reflist , 2, refs= {{cite news , author=Brody, Jane E , title=In women, hernias may be hidden agony , newspaper=St. Louis Post-Dispatch , date=18 May 2011 , url=http://www.stltoday.com/lifestyles/health-med-fit/health/jane-brody/article_7e2638ac-8959-57bb-9931-6f3aa084f3a1.html {{cite journal , vauthors=Bittner JG, Edwards MA, Harrison SJ, Li K, Karmin PN, Mellinger JD , title=Laparoscopic repair of a right paraduodenal hernia , journal=JSLS , volume=13 , issue=2 , pages=242–9 , year=2009 , pmid=19660226 , pmc=3015939 {{cite journal , author=Petersen W, title=Über Darmverschlinung nach der Gastroenterostomie , journal=Arch Klin Chir, volume=62, pages=94–114, year=1900 Hernias