• Clinical science

Abdominal hernias


Abdominal hernias are defined as the abnormal protrusion of intra-abdominal contents through congenital/acquired areas of weakness in the abdominal wall. Abdominal hernias are anatomically classified into four categories: ventral hernias (e.g., epigastric, umbilical hernia, incisional hernias), groin hernias (inguinal and femoral hernias), pelvic hernias (obturator, sciatic, and perineal hernias), and flank/lumbar hernias. Groin hernias are discussed in more detail in their respective learning cards. Inguinal, incisional, and umbilical hernias are the most common types of hernias. Persistently raised intra-abdominal pressure (e.g., due to ascites, pregnancy, intra-abdominal tumors, chronic cough, etc.) increases the risk of developing an abdominal hernia. Uncomplicated hernias are asymptomatic, nontender, completely reducible hernias with an expansile cough impulse. Complicated hernias include incarcerated, obstructed or strangulated hernias and are characterized by tenderness, irreducibility, features of bowel obstruction, and an absent cough impulse. Hernias with a narrow neck (e.g., femoral hernia, obturator hernia, paraumbilical hernia) have a higher risk of developing complications. Abdominal hernias are often diagnosed on clinical examination. Ultrasound/CT scans are useful in doubtful cases (e.g., obese patients). Complicated hernias, or those with a narrow neck, should be surgically repaired (primary repair/mesh repair). Asymptomatic hernias, with a wide neck do not require surgical repair.


Ventral hernias

Groin hernias

  • Inguinal hernia (direct/indirect)
  • Femoral hernia

Pelvic hernias (rare)

Flank hernias


Clinical features

  • Most are asymptomatic
  • Reducible hernias
    • Completely reducible non-tender mass on the abdominal wall (e.g., epigastric region, umbilicus, groin, etc.)
      • Increases on straining (e.g., coughing/lifting heavy objects)
      • Decreases on lying down
    • Edges of the fascial defect are palpable
    • Bowel sounds may be heard (If the content is bowel)
  • Irreducible/incarcerated hernias
  • Differential diagnosis: Abscess or hematoma
  • Treatment: Immediate surgical repair

The smaller the hernial orifice, the higher the risk of incarceration!



  • Usually a clinical diagnosis
  • Imaging: consider if the diagnosis is unclear and/or to identify contents of the hernial sac (e.g., loops of bowel)
    • Ultrasound (e.g., to identify an epigastric, spigelian, incisional or umbilical hernia)
    • CT scan (e.g., to identify a lumbar, obturator, perineal or sciatic hernia)


Incisional hernia

  • Definition: Herniation of intra-abdominal contents through an incisional scar from a previous abdominal surgery
  • Incidence: ∼15% of patients who have undergone an abdominal surgery develop incisional hernias
  • Risk factors
    • Upper midline laparotomy incisions (highest risk)
    • Wound dehiscence
    • Postoperative wound infection
    • Poor wound healing
    • Emergency abdominal surgeries
  • Clinical features
    • Most (∼ 75%) incisional hernias occur within 3 years of surgery
    • Mass/protrusion at the site of the incisional scar which increases with coughing/straining
    • Edges of the hernial defect can be palpated on reducing the hernia
  • Treatment
    • Conservative management: indications
      • Asymptomatic incisional hernias, with a wide neck (> 5–7 cm);
      • Patients who are at a high anesthetic risk (advanced age, multiple comorbidities) can be observed
    • Surgery: Indicated in symptomatic/complicated hernias or those with a narrow neck
      • Small incisional hernias (< 3 cm defect): primary repair
      • Larger incisional hernias: hernioplasty (mesh repair)
  • Recurrence: ∼ 30% of incisional hernias will recur after surgical repair (depending on the technique used)


Umbilical hernia

Umbilical hernias
Congenital umbilical hernia Acquired umbilical hernia
True (direct) umbilical hernia Paraumbilical hernia
  • Common disorder ( ∼ 15% of infants)
  • Uncommon in adults
  • ∼ 5% of all abdominal hernias
Site of hernial defect
  • The umbilical orifice
  • The umbilical orifice
  • Adjacent to the umbilical orifice (superior/inferior/lateral)
  • Congenitally weak abdominal wall defect
  • Congenitally weak abdominal wall defect
  • Acquired abdominal wall defect
Risk factors
  • Persistently raised intra-abdominal pressure
  • Persistently raised intra-abdominal pressure
Clinical features
  • Mass protruding through the umbilicus
  • Mass increases on crying/coughing/straining; reduced in size on lying down
  • Hernia can be completely reduced (unless complicated)
  • Mass protruding through the umbilical orifice
  • Mass protruding adjacent to the umbilical orifice pushing the umbilicus into a crescent shape
  • Fascial defect is small

Risk of developing complications


  • Low
  • Low
  • High
  • Conservative: ∼ 90% will spontaneously close by 5 years of age
  • Surgery (rarely necessary)
  • Surgery (primary repair/mesh plasty): All paraumbilical hernias
Differential diagnosis
  • Diagnosis is usually clear
  • Diagnosis is usually clear


last updated 06/13/2019
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