A hernia is the abnormal exit of tissue or an organ, such as the bowel, through the wall of the cavity in which it normally resides. Hernias come in a number of different types.
Hernia of abdominal wall and Ascites.
Types of abdominal and pelvic herniae
- Epigastric: a hernia through the fibres of the linea alba.
- Femoral: a hernia through the femoral canal, medial and inferior to the inguinal canal.
- Incisional: an iatrogenic hernia, occuring in 2–10% of all abdominal operations, secondary to breakdown of the surgical closure site from prior surgery. Recurrence rates approach 20 45% following repair.
- Inguinal: can be subdivided into indirect and direct. An indirect inguinal hernia passes along the inguinal canal and the hernial sac may or may not be limited to the inguinal canal. The neck of the sac lies lateral to the inferior epigastric artery. A direct inguinal hernia passes directly forward through the defect in the posterior wall of the inguinal canal, and the neck of the hernia lies medial to the inferior epigastric artery.
- Internal: herniation of bowel through defects in the peritoneum, omentum, mesentery or band of adhesions.
- Lumbar: hernia through the lumbar triangle. These tend to have a wide neck.
- Obturator: the hernia passes through the obturator foramen, following the path of the obturator nerves and muscles. Because of its anatomic position, this hernia presents more commonly as a bowel obstruction than as a protrusion of bowel contents.
- Peri-umbilical: herniation of abdominal contents through the periumbilical tissues.
- Richter: occurs when only the antemesenteric border of the bowel herniates through a fascial defect, and may lead to incarceration or strangulation of the focal herniated segment. It may occur with any of the various abdominal herniae and is particularly dangerous, as the strangulated bowel may be reduced spontaneously, leading to perforation and peritonitis.
- Spigelian: this rare form of abdominal wall hernia occurs through the semilunar line along the lateral aspect of the rectus sheath.
- Umbilical: herniation of abdominal contents through the umbilicus
- The clinical presentation of a hernia depends upon the site, size and hernial sac contents. Complications include incarceration, irreducibility, obstruction and strangulation.
- Plain X-Ray: not usually the modality of choice for diagnosing herniae; however, it is of use when bowel obstruction, secondary to a hernia, is suspected. Occasionally identified incidentally on a barium study.
- USS: useful to localise herniae and for differentiating from other causes of a palpable lump such as solid masses or a haematoma.
- CT and MRI: although US can provide good resolution of many superficial herniae, CT may provide more information regarding internal herniae.
- This technique is less frequently used now as there are other lessinvasive modalities available.
- A spinal needle is introduced into the peritoneal cavity and radiographic contrast injected.
- The patient is asked to cough and perform the valsalva manoeuvre to demonstrate contrast in the hernial sac.
Herniogram following installation of water soluble contrast into the peritoneal cavity. Peritoneal indentations and fossae of the anterior abdominal wall and their relation to the sites of groin hernia. 1, median umbilical ligament (obliterated urachus); 2, medial umbilical ligament (obliterated umbilical arteries); 3, lateral umbilical ligament (containing inferior epigastric arteries). Sites of possible herniae: A, lateral fossa (indirect inguinal hernia); B, medial fossa (direct inguinal hernia); C, supravesical fossa (supravesical hernia).
- A-Z of Abdominal Imaging, Series Editor R. R. Misra: 194, 195.
- wikipedia: Hernia.
- Video (YouTube: medhepatogastro): https://www.youtube.com/channel/UCpoFNft5jAgtg2ng9CGhLEQ?sub_confirmation=1