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Inguinal hernias

An inguinal hernia is the protrusion of abdominal contents through the inguinal canal.

Anatomy of the inguinal canal and inguinal ligament


  • Inguinal ligament = ASIS to pubic tubercle
  • Inguinal canal = deep inguinal ring to superficial inguinal ring 
    • Inguinal ring positions 
      • Deep inguinal ring (start of inguinal canal) = midpoint of the inguinal ligament
      • Superficial inguinal ring (end of inguinal canal) = superior to the pubic tubercle
    • Borders of the inguinal canal MALT
      • Muscle (internal oblique) – ROOF
      • Aponeurosis (external oblique) – ANTERIOR
      • Ligament (inguinal ligament) – FLOOR
      • Tendon (transversalis fascia) – POSTERIOR
    • Contents
      • Males: spermatic cord and ilioinguinal nerve

   Spermatic cord contains:

  • 3 arteries: testicular artery, artery to vas deferens, cremasteric artery
    • 3 nerves: genitofemoral nerve, autonomic nerves, ilioinguinal nerve (outside cord)
    • 3 other structures: vas deferens, pampiniform plexus of veins, lymphatic vessels
    • Females: round ligament of the uterus and ilioinguinal nerve 
  • Points to remember
    • Midpoint of the inguinal ligament (midpoint between the ASIS and pubic tubercle) = deep inguinal ring position
    • Mid-inguinal point (midpoint between the ASIS and pubic symphysis) = femoral artery position

Direct vs indirect inguinal hernia

  • Direct inguinal hernia (40%) 
    • Herniated abdominal contents come directly out of abdomen in a straight line 
    • Penetrate through the superficial inguinal ring
    • If reduced, cannot be controlled by applying pressure over the deep inguinal ring
  • Indirect inguinal hernia (60%)
    • Herniated abdominal contents run in the inguinal canal
    • Penetrate through the deep inguinal ring
    • Can go right the way down the canal into the scrotum in men (inguinal-scrotal hernia)
    • May occur due to failure of the closure of the processus vaginalis
    • If reduced, can be controlled by applying pressure over the deep inguinal ring

Inguinal hernia vs femoral hernia

  • Femoral hernia is inferior and lateral to the pubic tubercle (through femoral canal) – more common in females
  • Direct inguinal hernia is superior to the pubic tubercle (position of superficial inguinal ring) – more common in males
  • Indirect inguinal hernia can occur anywhere between the deep inguinal ring and the scrotum

Hernia terminology

ReducibleCan be pushed back into the abdomen by applying pressure
IrreducibleCannot be pushed back into the abdomen by applying pressure
ObstructedLumen if herniated part of bowel is compressed so contents cannot pass, causing obstructive symptoms
StrangulatedVasculature to herniated bowel is compressed, causing ischaemia


  • Watch and wait: for small, asymptomatic hernias
  • Open repair: for irreducible, obstructed or strangulated hernias
  • Open/laparoscopic mesh repair: for large or symptomatic hernias