Pathophysiology

• Acquired condition

• Caused by weakening of the transversalis fascia

  • Commonly secondary to conditions resulting in increased intraabdominal pressure (e.g., chronic obstructive pulmonary disease with chronic coughing, constipation)

  • May be associated with long-term glucocorticoid use

• Medial to the inferior epigastric blood vessels (within Hesselbach triangle) and lateral to the rectus abdominis

• Hernial sac protrudes directly through the posterior wall of the inguinal canal (without involvement of the spermatic cord or round ligament of the uterus)

• Only herniates through the superficial (external) ring

• Only surrounded by the external spermatic fascia

• Most commonly results from incomplete obliteration of processus vaginalis during fetal development (but can also be acquired).

• May not become apparent until adulthood despite being present since birth.

• Lateral to the inferior epigastric blood vessels (outside Hesselbach triangle)

• Runs from the deep inguinal ring through the inguinal canal to the superficial (external) inguinal ring (in men, along with the spermatic cord)

• Surrounded by the external spermatic fascia, cremasteric muscle fibers, and internal spermatic fascia

• Indirect inguinal hernia may be associated with a communicating hydrocele.

"The DIRECT path leads through the MiDdle, the INDIRECT path goes beLow." (DIRECT hernias lie MeDial and INDIRECT hernias lie Lateral to the inferior epigastric vessels)