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

Anatomy

• 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 contents
        • 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 

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 hernias 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

Management

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

Questions

Some related OSCE stations

1. Abdominal exam
2. Hernia
3. Lots more stations can be found here!