Inguinal

• Most common type of hernia
• An inguinal hernia is an abnormal protrusion of abdominopelvic contents through the superficial inguinal ring into the groin.
• Anatomy:

  • Inguinal ligament runs between the anterior superior iliac spine (ASIS) and the pubic tubercle
  • Inguinal canal runs just above the inguinal ligament
  • Inguinal canal provides a passageway between the peritoneal cavity and the external genitalia - in men transmits the spermatic cord to the testis. In women it contains the round ligament
  • Inguinal canal carries the ilioinguinal nerve and the genital branch of the genitofemoral nerve in both sexes
• • The deep ring: orifice of transversalis muscle fascia located just above the mid-point of the inguinal ligament - lateral to inferior epigastric vessels
  • The superficial ring: opening in external oblique muscle - lies just above and lateral to he pubic tubercle - medial to inferior epigastric vessels
• Hesselbach triangle boundaries:

  • Medial - lateral border of the rectus abdominis muscle
  • Lateral - inferior epigastric vessels
  • Inferior - inguinal ligament
• Direct inguinal hernia:

  • Caused by weakness in the posterior wall of the inguinal canal - Hesselbach's triangle
  • Abdominal contents (usually just fatty tissue, sometimes bowel) are forced directly through this defect into the inguinal canal
  • The hernia enters the canal medial to the deep ring and exits via the superficial ring
• Indirect inguinal hernia:

  • Instead of piercing the posterior wall of the inguinal canal, the abdominal contents enter the deep ring
  • Pass along the length of the inguinal canal and exit via the superficial ring
  • Some are congenital and develop due to incomplete closure of the processus vaginalis - typically in infants and children
  • More likely to manifest into the scrotum
• Inguinal canal:

  • forms during embryological development
  • In males - projection of the peritoneum called the processus vaginalis herniates through the abdominal body wall to allow testes to descend from abdomen to the scrotum
  • Once the testes are in place the processus vaginalis is obliterated closing off the communication between the abdomen and scrotum
  • Leaves canal that allows structures to pass from the abdomen to the external genitalia
• In men the inguinal canal contains:

  • Nerves
  • Spermatic cord which includes:
  • Covered by cremaster muscle
  • Arteries
  • Veins
  • Nerves
  • Lymphatics
  • Vas deferens
  • Fused shut processus vaginalis
• Men referral for surgical management:

  • Strangulation/obstruction - emergency
  • Incarceration - urgent
  • Symptomatic but reducible - routine
  • No symptoms and reducible - conservative management but can do routine referral if patient wants
• All groin hernias in women need urgent referral due to increased risk of incarceration or strangulation, and it is harder to differentiate between an inguinal and femoral hernia
• Some patients may report pain or altered sensation over the scrotum or inner thigh due to compression of the ilioinguinal nerve
• Management:

  • Mesh repair is the gold standard
  • Can be via open repair ( preferred for larger hernias) or laparoscopic surgery (preferred for recurrent or bilateral hernias)
• Aetiology and risk factors:

  • Much more common in men due to the anatomy of the inguinal canal
  • Incidence peaks at age 70
  • Low BMI seems to be a risk factor - more intra-abdominal fatty tissue which covers and protects the deep inguinal ring