Internal hernia
Updates to Article Attributes
Internal hernias are protrusions of the viscera through the peritoneum or mesentery but remaining within the abdominal cavity.
Epidemiology
InternalInternal hernias have a low incidence of <1%, and represent a relatively small amount of presentations, of ~5% 1.
Clinical presentation
The most common presentation is an acute obstruction of small bowel loops that develops through normal or abnormal apertures.
Internal hernias not infrequently self-resolve, making imaging at the time of symptomatology vital.
Pathology
The orifice that the small bowel herniates through is usually a pre-existing anatomic structures, such as foramina, recesses, and fossae (e.g. fossa of Landzert).
Pathologic defects of the mesentery and visceral peritoneum, such as from congenital maldevelopment of the mesenteries, and surgery also create potential internal herniation orifices.
Types of internal hernias include:
- left and right paraduodenal hernias (most common; ~55% 1)
- lesser sac (foramen of Winslow) hernia
- pericaecal hernia
-
sigmoid mesocolon hernias
- intersigmoid hernia
- transmesosigmoid hernia
- intramesosigmoid hernia
-
small bowel mesentery internal hernia
- transmesenteric hernia
- intramesenteric hernia
- transomental hernia
- supravesical hernia
- pelvic internal hernia
- falciform ligament hernia
- internal hernia due to gastric bypass surgery
Radiographic features
In contemporary practice virtually all patients undergo CT, which is the gold standard imaging modality. Traditionally barium studies were performed and may still on occasion be used in niche circumstances.
CT
The appearance depends on the particular internal hernia. Common features include:
- encapsulation of distended bowel loops within an abnormal location
- arrangement or crowding of small-bowel loops within a hernial sac
- evidence of obstruction with segmental dilatation and stasis
- mesenteric vessel abnormalities
- engorgement, crowding, twisting, stretching of mesenteric vessels
Fluoroscopy
The appearances on barium studies vary depending on the type and site of the internal hernia:
- clustering of small bowel loops
- distended bowel proximal to the site of obstruction
- abnormal site or displacement of normal parts of the gastrointestinal tract
-<p><strong>Internal hernias</strong> are protrusions of the viscera through the <a href="/articles/peritoneum">peritoneum</a> or <a href="/articles/mesentery">mesentery</a> but remaining within the <a href="/articles/abdominal-cavity">abdominal cavity</a>.</p><h4>Epidemiology</h4><p> Internal hernias have a low incidence of <1%, and represent a relatively small amount of presentations, of ~5% <sup>1</sup>.</p><h4>Clinical presentation</h4><p>The most common presentation is an <a href="/articles/small-bowel-obstruction">acute obstruction of small bowel loops</a> that develops through normal or abnormal apertures.</p><p>Internal hernias not infrequently self-resolve, making imaging at the time of symptomatology vital.</p><h4>Pathology</h4><p>The orifice that the small bowel herniates through is usually a pre-existing anatomic structures, such as foramina, recesses, and fossae (e.g. fossa of Landzert).</p><p>Pathologic defects of the <a href="/articles/mesentery">mesentery</a> and visceral peritoneum, such as from congenital maldevelopment of the mesenteries, and surgery also create potential internal herniation orifices. </p><p>Types of internal hernias include:</p><ul>- +<p><strong>Internal hernias</strong> are protrusions of the viscera through the <a href="/articles/peritoneum">peritoneum</a> or <a href="/articles/mesentery">mesentery</a> but remaining within the <a href="/articles/abdominal-cavity">abdominal cavity</a>.</p><h4>Epidemiology</h4><p>Internal hernias have a low incidence of <1%, and represent a relatively small amount of presentations, of ~5% <sup>1</sup>.</p><h4>Clinical presentation</h4><p>The most common presentation is an <a href="/articles/small-bowel-obstruction">acute obstruction of small bowel loops</a> that develops through normal or abnormal apertures.</p><p>Internal hernias not infrequently self-resolve, making imaging at the time of symptomatology vital.</p><h4>Pathology</h4><p>The orifice that the small bowel herniates through is usually a pre-existing anatomic structures, such as foramina, recesses, and fossae (e.g. fossa of Landzert).</p><p>Pathologic defects of the <a href="/articles/mesentery">mesentery</a> and visceral peritoneum, such as from congenital maldevelopment of the mesenteries, and surgery also create potential internal herniation orifices. </p><p>Types of internal hernias include:</p><ul>
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