An inguinal hernia is the protrusion of viscera or abdominal contents through the superficial inguinal ring. This viscera is normally made up of some small bowel, but not always. Inguinal hernias can either enter this ring directly through the deep inguinal ring or indirectly through the posterior wall of the inguinal canal.


  • Incidence: 10.00 cases per 100,000 person-years
  • Peak incidence: 50-60 years
  • Sex ratio: 1:1
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Clinical features

Hernias should be reducible, meaning that the herniated tissue can be pushed back into place in the abdomen through the defect using a hand. If a hernia cannot be reduced it is referred to as an incarcerated hernia, these hernias are at risk of strangulation.

Indications that a hernia is at risk of strangulation include:
  • Episodes of pain in a hernia that was previously asymptomatic
  • Irreducible hernias

Symptoms of strangulated hernias include:
  • Pain
  • Fever
  • Increase in the size of a hernia or erythema of the overlying skin
  • Peritonitic features such as guarding and localised tenderness
  • Bowel obstruction e.g. distension, nausea, vomiting
  • Bowel ischemia e.g. bloody stools


Imaging can be used in cases of suspected strangulation, however, it is not considered necessary and is more useful in excluding other pathologies. However, if obstruction is suspected an abdominal X-ray or CT is useful in assessing the patient and all patients with suspected perforation should receive an erect chest X-ray A full blood count and arterial blood gas analysis can help point towards the diagnosis by showing:
  • Leukocytosis
  • Raised lactate


Strangulation is a surgical emergency where the blood supply to the herniated tissue is compromised, leading to ischemia or necrosis. As most inguinal hernias are formed from small bowel, this impaired blood flow can cause the bowel tissue to be permanently lost or to perforate. Strangulation occurs in around 1 in 500 cases of all inguinal hernias.

Repair involves immediate surgery, either from an open or laparoscopic approach with a mesh technique. This is the same technique used in elective hernia repair, however, any dead bowel will also have to be removed. While waiting for the surgery, it is not recommended that you manually reduce strangulated hernias, as this can cause more generalised peritonitis.