Clinical Cases - Inguinal Region
S.T., a 35-year-old man, was carrying furniture out to a moving van in preparation for his family's move to a new home. When S.T. strained to pick up a particularly heavy coffee table, he suddenly felt a sharp pain in his right groin. Later, he noticed that a painful bulge had developed in his groin which disappeared when he laid on his back. He did not like going to the doctor, so he ignored the condition. After several months, the pain and the bulge in his groin increased and he finally consented to see a physician. On examination, the physician observed a swelling which began about midway between the anterior superior iliac spine and the midline, progressed medially for about 4 cm, and then turned toward the scrotum . Taking the history and physical findings into account, the physician made a diagnosis of indirect inguinal hernia and scheduled S.T. for surgery . The hernia was successfully repaired, and S.T. was released from the hospital a few days later.

Questions to consider:
  1. What abdominal wall layers must be incised with a small midline incision in order to access the abdominal cavity?
    A midline incision would pass through skin, superficial fascia (outer fatty and inner membranous layers), linea alba, transversalis fascia, extraperitoneal connective tissue, median umbilical ligament, and parietal peritoneum.
  2. What defines this hernia as an indirect inguinal hernia rather than a direct inguinal hernia? List the key features of each.
    This hernia is an indirect inguinal hernia because it traverses the inguinal canal. Indirect inguinal hernial sacs enter the inguinal canal at the deep inguinal ring lateral to the inferior epigastric vessels. Depending on the severity, the hernial sac may or may not extend through the superficial inguinal ring and into the scrotum or labium majus. Indirect inguinal hernias are more common in males than in females, and may be congenital or the result of an injury, as in the case above. Direct inguinal hernias bulge through the weak fascia of the abdominal wall directly behind the superficial inguinal ring and medial to the inferior epigastric vessels. Direct inguinal hernias are common in elderly men with weak abdominal muscles. Direct inguinal hernias rarely enter the scrotum.
  3. What caused the bulge? What body layers would surround it as it proceeded into the scrotum and what abdominal layers are they derived from?
    The bulge was most likely caused by a loop of small intestine that traversed the inguinal canal. The body layers surrounding the intestinal bulge in the scrotum are as follows: skin, dartos muscle, membranous layer of the superficial fascia, external spermatic fascia (from the external oblique aponeurosis), the cremasteric fascia (from the internal oblique aponeurosis), and the internal spermatic fascia (from the transversalis fascia).
  4. Why would it be necessary to repair a hernia like the one described above as quickly as possible?
    An indirect inguinal hernia in which the bowel becomes entrapped can rapidly lead to an intestinal obstruction and to strangulation of the loop of bowel projecting into the inguinal canal. If not treated immediately, gangrene of the intestine may set in within 12 hours.
  5. How is the inguinal canal formed, and which structures are associated with the inguinal canal in the male? in the female?
    The inguinal canal forms as the gubernaculum draws the testis down into the scrotum during fetal development in the male, or during the analogous development in the female (animation). The deep inguinal ring persists as a defect in the transversalis fascia formed as the gonadal structures descended and the superficial inguinal ring is formed by the lateral one-half of the pubic crest and the lateral and medial crura of the external abdominal oblique aponeurosis. The spermatic cord passes through the inguinal canal in the male and the round ligament of the uterus traverses the canal in the female. The ilioinguinal nerve also passes through the inguinal canal in both sexes.
  6. What other abdominal or pelvic regions, aside from the inguinal canal, are susceptible to herniation ?
    Umbilical hernia--Herniation of abdominal contents through a weakness in the abdominal wall behind the umbilicus. This is common in infants.

    Femoral hernia--Abdominal contents pass deep to the inguinal ligament into the femoral triangle of the thigh. These herniae should not be confused with inguinal herniae because they present below and lateral to the pubic tubercle, whereas inguinal herniae are found above and medial to the pubic tubercle.

    Obturator herniae--These herniae pass into the medial thigh via the obturator foramen in the pelvis.

    Lumbar herniae--These emerge through a muscular weakness in the region of the lumbar triangle, which has the following borders: Posterior margin of the external abdominal oblique (anterior border of the triangle), anterior margin of the latissimus dorsi (posterior border of the triangle), iliac crest (inferior border of the triangle), and the internal abdominal oblique and the transversus abdominis muscles (floor of the triangle).

    Incisional herniae--These may occur anywhere a weakness in the abdominal wall occurs as a result of an incisional wound, surgical or otherwise.

  7. What is the definition of an inguinal hernia? What is the male to female ratio of incidence of direct inguinal hernias?
    An abdominal viscus that pushes through a congenital or acquired defect in the lower abdominal wall. The male:female ratio is 9:1.
  8. What are common causes of direct inguinal hernias?
    Increased intraabdominal pressure caused by straining, heavy lifting, heavy exercise, obesity, chronic cough.
  9. What are the boundaries of Hesselbach's (inguinal) triangle?
    Laterally: Deep (inferior) epigastric artery
    Medially: Lateral rectus abdominis muscle border
    Inferiorly: Inguinal ligament
  10. Do you know your eponyms? What are the following structures? (NOTE: FYI only - we will not exam on these)
  1. Poupart's ligament - Inguinal ligament
  2. Cooper's ligament - Pectineal ligament
  3. Gimbernat's ligament - Lacunar ligament
  4. Colles' ligament - Reflected inguinal ligament
  5. Henle's ligament - Falx inguinalis
  6. Hesselbach's ligament - Interfoveolar ligament (thickened transversalis fascia anterior to the epigastric vessels).
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