Inguinal Hernia Case File

Inguinal Hernia Case File

Eugene C. Toy, MD, Lawrence M. Ross, MD, PhD, Han Zhang, MD, Cristo Papasakelariou, MD, FACOG

CASE 18

A 44-year-old man complains of discomfort in his right upper thigh for the past 6 months. He works in the garden department of a home improvement center. On examination, there is tenderness at the right inguinal area. When the patient performs a Valsalva maneuver (bearing down to increase intraabdominal pressure), a bulge appears superior to the inguinal crease near the pubic bone.

⯈ What is the most likely diagnosis?

⯈ What is the anatomical defect associated with this condition?

ANSWER TO CASE 18:

Inguinal Hernia

Summary: A 44-year-old man who works in the garden department of a home improvement center has a 6-month history of right groin pain. There is inguinal tenderness and a bulge following a Valsalva maneuver.

• Most likely diagnosis: Inguinal hernia

•  Associated anatomical defect: Protrusion of an abdominal organ into the inguinal canal

CLINICAL CORRELATION

A hernia is defined as an abnormal protrusion of a structure through tissues that normally contain it. Inguinal hernias are the most common type of hernia, occurring in men and women, although they occur much more frequently in men. This patient’s age and his occupation, which requires frequent lifting activity, suggest a direct or acquired inguinal hernia. Loss of tone in the musculature in the inguinal region predisposes to progressive stretching of the parietal peritoneum into the posterior inguinal canal with repeated increased intraabdominal pressure associated with the lifting activity. If the patient were a young man or child, an indirect or congenital inguinal hernia would be a more likely diagnosis. With an indirect hernia, the parietal peritoneum at the deep inguinal ring exists as a fingerlike protrusion into the inguinal canal. This is the result of faulty closure of the embryonic outpouching of peritoneum into the scrotum, called the process vaginalis. Indirect inguinal hernias enter the deep inguinal ring, stretch peritoneal tissue with repeated increases in intraabdominal pressure, traverse the length of the inguinal canal, and enter the scrotum. Surgical repair of the tissue defect is indicated to prevent incarceration, infarction, and necrosis of the herniated tissue, typically a loop of small intestine.

APPROACH TO:

The Inguinal Region

OBJECTIVES

1. Be able to describe the anatomy of the inguinal region

2. Be able to discern the anatomical basis for an indirect versus a direct inguinal hernial classification

DEFINITION

VALSALVA MANEUVER: Increase intraabdominal pressure by attempting to exhale with a closed glottis

DISCUSSION

The inguinal region is the junction between the lower anterior abdominal and the upper anterior thigh. It is the site at which several structures enter and exit the abdomen and therefore is an area of potential weakness in males and females. The inguinal (Poupart) ligament is an important anatomical structure and key landmark for this region. It is the thickened, rolled underedge of the inferior portion of the external abdominal oblique aponeurosis. It extends from the anterior superior iliac spine to the pubic tubercle and fuses inferiorly with the fascia lata (deep fascia) of the anterior thigh. At the pubic tubercle, the inguinal ligament continues posterolaterally on the superior pubic ramus (pectin of the pubic bone) as the pectineal (Cooper) ligament. At the point where these two ligaments are continuous and change directions, a ligamentous reflection fills the interval, forming the lacunar (Gimbernat) ligament.

The lacunar ligament forms a rigid medial margin for the femoral ring, leading to the femoral canal, the site for femoral hernias (Figure 18-1).

Although the external abdominal oblique muscle and aponeurosis constitute an essentially complete musculotendinous structure (except for the superficial inguinal ring), the internal abdominal oblique and transversus abdominis muscles are deficient because they originate from the iliopsoas fascia and arch medially to their tendinous (falx inguinalis) insertions on the pubic tubercle (Figure 18-2).

Structures enter and exit the abdomen superior to the inguinal ligament through an oblique passage known as the inguinal canal. The canal is frequently described as a tunnel, with openings, walls, floor, and so on. These boundary features are listed in Table 18-1.

Two points in Table 18-1 are of anatomical and clinical significance. First, as a result of the arching of the internal oblique and transversus abdominis muscles, the posterior wall of the canal is deficient and weak, as it is formed only by the transversalis fascia and parietal peritoneum. However, with increased intraabdominal pressure (as in lifting, a bowel movement, etc.), these muscles contract and descend

Figure 18-1. Inner surface of Hesselbach triangle. (Reproduced, with permission, from Lindner HH.

Clinical Anatomy. East Norwalk, CT: Appleton & Lange, 1989:288.)

Figure 18-2. The ilioinguinal region. (Reproduced, with permission, from Lindner HH. Clinical Anatomy. East Norwalk, CT: Appleton & Lange, 1989:291.)

in a shutterlike fashion, thus reinforcing the posterior wall. Second, the outpouching of the transversalis fascia to form the deep inguinal ring occurs immediately laterally to the inferior epigastric vessels (see Case 17 for a discussion of their course). In addition, at the medial portion of the inguinal ligament on the interior of the abdominal wall, a clinically important inguinal (Hesselbach) triangle is formed by some of these structures. This triangle is formed by the inguinal ligament, inferior epigastric vessels, and lateral margin of the rectus abdominis muscle and corresponds to the area where the posterior wall of the canal is deficient because of the arching of the abdominal wall muscles described above.

In females, the inguinal canal is traversed by the round ligament of the uterus; in males, the spermatic cord (ductus deferens and associated vessels and nerves) passes through the canal. The ilioinguinal nerve is found in the canal in both sexes.

The inguinal region and canal serve as the site for inguinal hernias. Although hernias occur in both sexes, they are far more common in males. There are two types of inguinal hernias: indirect and direct. Indirect or congenital inguinal hernias tend to occur in young males. During embryonic descent of the testes, an outpouching

Table 18-1 • BOUNDARIES OF THE INGUINAL CANAL
Anterior Wall	Posterior Wall	Floor	Roof	External Opening	Internal Opening
Aponeurosis of external abdominal oblique muscle	Transversalis fascia and parietal peritoneum	Inguinal ligament and lacunar ligament medially	Arching fibers internal oblique and transversus abdominis muscle	Superficial inguinal ring: triangular opening in external oblique aponeurosis	Site of outpouching of transversalis fascia: covered with parietal peritoneum

of parietal peritoneum, the tunica vaginalis, pushes through the lower abdominal wall, encountering first the transversalis fascia (thus forming the deep inguinal ring), slipping inferior to the transversus abdominis muscle, but catching the lower margin of the internal abdominal oblique muscle, and then pushing through the external abdominal oblique muscle (forming the superficial inguinal ring). The testes descend into the scrotum along the path created by the tunica vaginalis (and the gubernaculum). In normal development, this outpouching fuses and closes. If it does not fuse and close, a predisposing complete or partial path for the abnormal migration of an abdominal organ (usually small intestine) is established. The loop of small intestine would pass through the deep inguinal ring and the inguinal canal, and possibly through the superficial ring into the scrotum. By definition, indirect inguinal hernias leave the abdominal cavity lateral to the inferior epigastric vessels (through the deep inguinal ring).

Direct inguinal hernias are also called acquired inguinal hernias because they are seen in older males and are related to strenuous activity that increases intraabdominal pressure. It is believed that with aging there is loss of tone in the abdominal musculature, and the shutterlike actions described above for the internal abdominal oblique and transverses abdominis are diminished or lost. This predisposes abdominal organs to push directly anterior through the parietal peritoneum and transversalis fascia in the inguinal triangle area and into the posterior wall of the canal. Because of the larger herniation, these hernias tend not to enter the scrotum. Direct inguinal hernias by definition leave the abdomen medial to the inferior epigastric vessels because these vessels form the lateral boundary of the triangle.

COMPREHENSION QUESTIONS

18.1 As a physician examining the inguinal region of a patient, you note that the inguinal ligament will be a key landmark. This structure is a feature derived from which of the following?

A. Superficial fascia

B. Fascia lata of the thigh

C. Aponeurosis of the external abdominal oblique

D. Aponeurosis of the internal abdominal oblique

E. Aponeurosis of the transversus abdominis

18.2 As you continue your examination to check for the presence of an inguinal hernia, you insert the tip of your finger into the superficial inguinal ring. This is an opening in which of the following?

A. Superficial fascia

B. Fascia lata of the thigh

C. Aponeurosis of the external abdominal oblique

D. Aponeurosis of the internal abdominal oblique

E. Aponeurosis of the transversus abdominis

18.3 You are in the process of repairing a direct inguinal hernia. Which of the following anatomical relations will you find during surgery?

A. The hernia will enter the deep inguinal ring.

B. The hernia will enter the femoral ring.

C. The hernia will lie lateral to the inferior epigastric vessels.

D. The hernia will lie medial to the inferior epigastric vessels.

E. The hernia will lie inferior to the inguinal ligament.

18.4 A 58-year-old man who works in a warehouse lifting heavy boxes visits his physician complaining of pain in the groin area. On exam, he is found to have a large bulge superior to the right inguinal ligament. Imaging shows that the bulge arises medial to the inferior epigastric artery. This condition is most likely due to weakness of the

A. Inguinal ring

B. Femoral ring

C. Rectus abdominis muscle

D. Transversalis fascia

E. Cremasteric muscle

ANSWERS

18.1 C. The inguinal ligament is the inferior edge of the aponeurosis of the external abdominal oblique muscle.

18.2 C. The superficial inguinal ring is an opening in the aponeurosis of the external abdominal oblique muscle.

18.3 D. Direct inguinal hernias occur through the inguinal triangle, and the inferior epigastric vessels form the lateral boundary of this triangle. Hence, these vessels are lateral to the hernia.

18.4 D. Direct inguinal hernias usually present in older men, medial to the inferior epigastric vessels, and because of weakness of the transversalis fascia. Indirect hernias are present in male infants and are due to failure of the inguinal ring to close; the hernia is typically lateral to the inferior epigastric vessels.

ANATOMY PEARLS

⯈ The external abdominal oblique aponeurosis forms the anterior wall and floor of the inguinal canal (inguinal ligament) and the superficial inguinal ring.

⯈ The deep inguinal ring lies immediately lateral to the inferior epigastric vessels.

⯈ Indirect inguinal hernias enter the deep inguinal ring (lateral to the epigastric vessels).

⯈ Direct inguinal hernias enter the inguinal triangle (medial to the epigastric vessels).

References

Gilroy AM, MacPherson BR, Ross LM. Atlas of Anatomy, 2nd ed. New York, NY: Thieme Medical Publishers; 2012:142−143, 147. 

Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 7th ed. Baltimore, MD: Lippincott Williams & Wilkins; 2014:203−206, 212−214. 

Netter FH. Atlas of Human Anatomy, 6th ed. Philadelphia, PA: Saunders; 2014: plates 245−247, 255−257.

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