Abdominal hernias are a protrusion of intraabdominal contents through a congenital or acquired defect in the abdominal wall. Abdominal hernias are broadly classified by location (anterior wall, lateral wall, groin, or pelvis) and presentation (reducible, irreducible, obstructed, or strangulated). Physiological states that increase intraabdominal pressure (e.g., ascites, pregnancy, obesity, intraabdominal tumors, chronic cough) increase the risk of developing an abdominal hernia. Clinical presentation ranges from an asymptomatic mass in reducible hernias, to pain, bowel obstruction, and systemic symptoms in strangulated hernias. Abdominal hernias are typically a clinical diagnosis made on physical examination. Imaging (e.g., ultrasound, CT scan) may be used if the examination is difficult or atypical, and before surgery. Treatment is primarily surgical repair with or without a mesh, though observation may be adequate in some patients. Emergency surgery is always required for an obstructed or strangulated (i.e., ischemic) hernia. Congenital umbilical hernias typically close spontaneously by 5 years of age and have a wide neck, and the risk of complications is low; surgical intervention is rarely necessary.
See “hernia types.” and ” ” for more detail on these
By anatomical location 
Anterior abdominal wall hernias
- Umbilical hernia: midline ventral hernia at the level of the umbilicus 
- Epigastric hernia: protrusion of intraabdominal contents through the linea alba, between the xiphoid process and the umbilicus
- Incisional hernia: protrusion of intraabdominal contents through an abdominal wall defect due to previous surgery
- Parastomal hernia: a subset of incisional hernias in which intraabdominal contents protrude through the abdominal wall defect created during stoma placement (e.g., colostomy)
Lateral abdominal wall hernias
- Lumbar hernia
- Spigelian hernia: herniation along the semilunar line; commonly adjacent to the arcuate line (i.e., below the umbilicus) 
- (direct or indirect)
- Pelvic hernias 
By degree of complication 
- Reducible hernia: Hernia contents can be completely returned to the peritoneal cavity.
- Irreducible hernia (also known as incarcerated hernia): Hernia contents cannot be completely returned to the peritoneal cavity. 
- Obstructed hernia: a hernia in which the lumen of the intestine within the hernial sac has become completely obstructed
- A hernia in which the contents of the hernial sac (e.g., omentum, bowel) have become ischemic due to a compromised vascular supply
- Richter hernia: a subset of strangulated hernias in which only the antimesenteric portion of the intestinal wall is trapped by the abdominal wall defect, causing ischemia without obstruction 
- Complex hernia: a hernia that is technically challenging to repair, requires a longer operative time, and has greater associated perioperative morbidity than a simple hernia 
Intermediate-sized abdominal wall defects have the highest risk of causing an incarcerated hernia. Small wall defects are less likely to allow a visceral protrusion and large wall defects are less likely to cause mechanical impingement of the contents of the hernial sac.
Reducible hernia 
- Symptomatic or asymptomatic mass or fullness
- Size decreases with recumbency
- Size increases with sitting, standing, and/or straining
- Nontender mass that returns to the peritoneal cavity with mild, externally applied pressure
- Visible or palpable cough impulse: expansion of the mass with increased abdominal pressure
- Edges of the fascial defect may be palpable.
- Bowel sounds may be present over the mass if part of the bowel is present in the hernial sac.
Irreducible (incarcerated) hernia 
- Chronic incarceration: nontender or minimally tender mass
- Acute incarceration: Mass may be painful.
- Neither recumbency nor external pressure significantly reduce mass size.
- Cough impulse may be present.
Obstructed hernia 
Strangulated hernia 
- Physical examination
Intestinal strangulation can lead to gangrene, which can be fatal if not treated promptly.
Unusual presentations 
- Pelvic hernias
- Spigelian hernia: localized pain and an ill-defined or no mass in the lower abdomen
- An abdominal hernia is usually a clinical diagnosis made on physical examination.
- Imaging may be necessary if the examination is difficult (e.g., due to tenderness, obesity, scarring) or presentation is atypical, and for surgical planning.
- Laboratory studies are indicated if strangulation or obstruction is suspected and as part of .
- For patients presenting with acute abdominal pain, see also “Approach to acute abdomen.”
- Unclear diagnosis, e.g., abdominal wall pain without a clinically apparent hernia
- Suspected complication, e.g., bowel obstruction or strangulation
- Obesity (BMI > 35 kg/m2)
- Recurrence of incisional hernias
- Planning for surgical repair
- CT abdomen
- MRI abdomen
- Abdominal x-ray: may be used to rapidly evaluate for bowel obstruction and perforation
- Direct visualization and quantification of the fascial defect(s)
- Presence of viscera in the hernial sac
- Strangulated hernia: signs of visceral ischemia 
- Obstructed hernia:
Laboratory studies 
Differential diagnoses of ventral hernias
Rectus sheath hematoma
- Definition: : an accumulation of blood within the rectus sheath that most commonly arises from the disruption of a branch of the inferior epigastric artery
- Etiology 
Clinical features 
- Acute onset abdominal pain
- Palpable abdominal mass
- Abdominal tenderness and/or guarding
- Carnett sign
- Fothergill sign
- Cullen sign (periumbilical ecchymosis)
- Grey Turner sign (flank ecchymosis)
- Signs of hypovolemic shock (e.g., tachycardia, hypotension)
- Diagnostics 
- Treatment 
Differential diagnoses of other hernias
- Pelvic and groin hernias
- Strangulated hernia
The differential diagnoses listed here are not exhaustive.
Surgical repair is the definitive treatment for abdominal wall hernias, but management with watchful waiting may be appropriate in select patients. See also “Incisional hernia” and “Umbilical hernia” for management specific to these hernia types.
Initial management 
- Reducible hernia or chronically irreducible hernia
- Acutely irreducible hernia without signs of obstruction or strangulation
Strangulated or obstructed hernia
- Obtain emergency surgery consult and begin supportive care as needed.
- Obstructed hernia without signs of strangulation: Consider manual hernia reduction. 
- Signs of strangulation: Consider IV broad-spectrum antibiotics (see “Empiric antibiotic therapy for intraabdominal infection”). 
Treat strangulated hernias and obstructed hernias as surgical emergencies, for which operative repair is indicated within hours to prevent complications (e.g., intestinal ischemia, sepsis, and death).
Manual hernia reduction 
- Indications: acutely incarcerated hernias with no signs of strangulation
- Preparation: Administer analgesia; consider the need for procedural sedation.
- Reduction successful
- Typically, patients are admitted for observation for at least 12 hours.
- Schedule early surgical repair (often performed during the same admission).
- Unsuccessful reduction or new signs of strangulation: prompt surgical intervention
- Reduction successful
- Complications: visceral rupture or perforation, peritonitis, worsened ischemia
Nonoperative and preoperative management
- Watchful waiting may be considered in selected patients. 
- If elective hernia repair is anticipated, consider starting (e.g., smoking cessation, weight loss) and optimization of chronic illnesses. 
- Hernia trusses and binders may improve patient comfort but have not been found to reduce the risk of acute hernia complications. 
Surgical management 
- Techniques (open or laparoscopic): include (i.e., with mesh) and (i.e., with sutures) 
- Complications following surgery include: 
- Definition: herniation of intraabdominal contents through an abdominal wall defect due to previous abdominal surgery
- Incidence: up to 20% after abdominal surgery 
- Risk factors 
- Clinical features 
- Treatment 
- Complications 
Parastomal hernia 
- A type of incisional hernia in which intraabdominal contents protrude through the abdominal wall defect created during stoma placement (e.g., )
- Diagnosis: usually clinical; imaging (CT or ultrasound) may be considered if the diagnosis is uncertain.
Congenital vs. acquired umbilical hernias 
|Congenital umbilical hernia || |
Acquired umbilical hernia 
|Site of hernial defect|| || |
|Risk factors|| |
Risk of developing complications
(incarceration, obstruction, strangulation, or rupture)
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