General Surgery (Board Review Series) 1st Edition

10

Hernias and Lesions of the Abdominal Wall

Traves D. Crabtree

1. Overview
2. An abdominal hernia

• is generally defined as a congenital or acquired defect in the fascia and musculature of the abdominal wall that may allow for protrusion of a peritoneal sac and structures within the peritoneum (e.g., bowel).

1. Epidemiology
2. The overall prevalence

• of spontaneous abdominal wall hernias is approximately 5%–10% over a lifetime.

2. The distribution of hernias
3. Inguinal hernias

• account for 80%of all spontaneous hernias.

1. Umbilical hernias

• account for approximately 15% of all hernias.

1. Femoral hernias

• account for approximately 5%.

1. All other types of herniasare very rare.
2. Definitions
3. A hernia is reducible

• when the contents of the hernia sac (e.g., intestines) can be returned to their normal anatomic domain.

2. A hernia is incarcerated

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• when the contents of the hernia sac cannot be reduced, trapping the contents of the hernia sac.
• Incarceration can lead to intestinal obstruction in the absence of ischemia.

3. A strangulated hernia

• results when the contents of an incarcerated hernia become ischemic secondary to tissue swelling and compromise of the blood supply.

4. A sliding hernia (Figure 10-1)

• occurs when the hernia sac is partially formed by the wall of an organwithout peritoneal covering (e.g., posterior cecum, ovary, bladder, sigmoid).

5. A Richter hernia (Figure 10-2)

• represents a partial herniationof the antimesenteric wall of the intestine.

1. This rare hernia can result in

• strangulation and necrosis in the absence of intestinal obstruction.

1. This is a dangerous hernia

• because inadvertent reduction of the necrotic segment during hernia repair may result in perforationand peritonitis.

6. A hernia sacmay rarely contain a Meckel's diverticulum (Littré's hernia).

• These hernias are similar to Richter's hernias in that strangulation and necrosis can occur in the absence of intestinal obstruction.

Figure 10-1. Right-sided sliding inguinal hernia. (Adapted with permission from Way LW: Current Surgical Diagnosis and Treatment, 10th ed. Stamford, CT, Appleton & Lange, 1994, p 717.)

1. Anatomy of the abdominal wall (Figure 10-3)
2. The rectus sheath

• Superiorly in the midline of the abdomen the rectus abdominis muscles are ensheathed in a thick anterior and posterior fascia known as the rectus sheath.

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2. Above the semicircular line of Douglas
3. The anterior rectus sheath

• is composed of the aponeurosis of the external oblique muscle and the anterior aponeurosis of the internal oblique.

1. The posterior rectus sheath

• is composed of the aponeurosis of the transversalis muscle and the posterior aponeurosis of the internal oblique.

Figure 10-2. Richter hernia. (Adapted with permission from Greenfield L: Surgery: Scienti.c Principles and Practice, 2nd ed. Philadelphia, Lippincott Williams & Wilkins, 1997, p 1218.)

Figure 10-3. Fascial layers of the abdominal wall. Above and Below indicate placement about the semicircular line of Douglas. A = skin; B = subcutaneous fat; C = external oblique muscle; D = internal oblique muscle; E = transversus abdominis muscle; F = transversalis fascia; G = preperitoneal fat; H = peritoneum; I = posterior layer of rectus sheath; J = rectus abdominis muscle; K = anterior layer of rectus sheath. (Adapted with permission from Lippincott Williams & Wilkins. Gray and Skandalakis: Atlas of Surgical Anatomy for General Surgeons. Baltimore, Williams & Wilkins, 1985, p 91.)

3. Below the semicircular line of Douglas

• all of the aponeuroses join to form the anterior rectus sheath with no fascia covering the rectus muscles posteriorly.

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1. Inguinal Hernias
2. Overview
3. Inguinal hernias

• occur with a male predominance (7:1).

2. The pathogenesis

• of inguinal hernias is incompletely understood.

1. A persistently patent processus vaginalis

• may contribute to the pathogenesis of indirect inguinal hernias.

1. Other contributing factorsmay include

• intrinsic abnormalities of collagen formation.
• chronic trauma.
• overstretching of fascial layers.
• chronic increases in intra-abdominal pressure (e.g., chronic cough or obstipation associated with an obstructing colon cancer).

1. Anatomy of the inguinal canal (Figure 10-4)

Figure 10-4. Anatomy of the inguinal region. (A) Superficial layer of the inguinal region. (B) Deep layers with external oblique fascia removed. (C) View of all fascial layers as the cord traverses the inguinal canal. (Adapted with permission from Lippincott Williams & Wilkins. Gray and Skandalakis: Atlas of Surgical Anatomy for General Surgeons.Baltimore, Williams & Wilkins, 1985, pp 93–95.)

1. Indirect inguinal hernias

• originate at the deep inguinal ring.
• are most frequently located anteromedial to the cord structures.
• pass lateral to the inferior epigastric vessels.

2. Direct inguinal hernias

• occur directly through the abdominal wall without passing through the deep inguinal ring (see Figure 10-4 B).

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1. Direct hernias occur through Hesselbach's triangle (Figure 10-5), and are bound

• medially by the lateral border of the rectus.
• laterally by the inferior epigastric vessel.
• inferiorly by the inguinal ligament (Poupart's ligament).

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1. Direct hernias pass

• medial to the inferior epigastric vessels.

3. A pantaloon hernia

• is characterized by a hernia with both a direct and an indirect component, surrounding the inferior epigastric vessels.

4. The conjoined tendon

• is composed of the medial aponeuroses of the internal oblique and transversus abdominis muscles.
• runs along the inferolateral border of the rectus muscle to attach to the pubic tubercle.
• A true conjoined tendon only occurs in approximately 25% of individuals.

Figure 10-5. Hesselbach's triangle. (Adapted with permission from Lippincott Williams & Wilkins. Gray and Skandalakis: Atlas of Surgical Anatomy for General Surgeons.Baltimore, Williams & Wilkins, 1985, p 96.)

1. Risk factors include

• advancing age.
• severe obesity.
• heavy exercise or lifting.
• chronic cough associated with chronic obstructive pulmonary disease (COPD).
• chronic constipation (e.g., associated with an obstructing colon cancer).
• chronic straining for urination (e.g., benign prostatic hyperplasia).
• ascites.

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• pregnancy.
• peritoneal dialysis.

1. Signs and symptoms
2. Many hernias are asymptomaticand are found during routine physical examination.
3. Other signsinclude

• a nontender groin mass.
• sudden onset of a painful mass after straining.
• scrotal pain or discomfort.

3. Hernias may present

• with signs and symptoms of a small bowel obstruction.

4. Indirect hernias

• are more likely to become incarcerated or strangulated compared with direct hernias.

1. Diagnosis

• of a hernia is based on identification during physical examination.

1. No other specific diagnostic testsare required for the diagnosis.

• Fever and or leukocytosis, along with abdominal pain, may suggest the presence of strangulationof bowel.

2. In general, it is difficult to distinguish

• a direct hernia from an indirect hernia on physical examination.

3. The differential diagnosismay include

• femoral hernia.
• lipoma of the spermatic cord.
• hydrocele of the cord (may transilluminate on examination).
• communicating hydrocele.
• congenital undescended testis (absence of testis in scrotum).
• varicocele.
• lymphadenopathy.
• hematoma formation.

1. Indications for surgery
2. Inguinal hernias

• require surgical repair because of the significant risk of complications associated with incarceration, obstruction, and strangulation.

2. A reducible hernia

• should be repaired electively.

1. The most effective measure of reduction

• is application of slow, constant pressure over the hernia sac.

1. Abdominal relaxation

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• can be facilitated by placing the patient in the supine position with the knees slightly flexed.

1. Mild anesthesia

• or sedation may also be beneficial.

3. Incarcerated hernias

• require urgent surgical repairwith reduction of the hernia sac because of the risk of subsequent obstruction or strangulation.

Figure 10-6. Bassini repair of an inguinal hernia. The transversalis fascia is approximated to the inguinal ligament. (Adapted with permission from Schwartz S: Principles of Surgery. 5th ed. New York, McGraw Hill, 1989, p 1538.)

1. Methods of surgical repair
2. Indirect hernias in children and young adultsmay be repaired by

• reduction of the hernia contents.
• high ligation and resection of the hernia sacnear the deep inguinal ring.
• simple tightening of the ring to reduce the potential space for herniation (Marcy repair).

2. Inguinal hernias in adultsare repaired

• by reduction of the hernia sac along with formal repair of the inguinal floorby several techniques.

1. The superficial Bassini repair (Figure 10-6) involves approximation of theconjoined tendon and transversalis fascia (superior) to the free edge of the inguinal ligament(inferior).
2. The deeper McVay repair (Cooper's ligament repair) (Figure 10-7)approximates the conjoined tendon and transversalis fascia to Cooper's ligament (lateral).

• This repair requires placement of a relaxing incision in the anterior rectus sheath because of the significant tension associated with this repair.

1. A Lichtenstein repair (Figure 10-8)involves insertion of synthetic mesh (e.g., polypropylene) over the hernia defect.

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1. The choice of repair

• is generally based on surgeon preference with no definitive data demonstrating a distinct advantage of one procedure over another.

Figure 10-7. McVay repair (Cooper's ligament repair) of an inguinal hernia. The transversalis fascia is approximated to Cooper's ligament. (Adapted with permission from Schwartz S: Principles of Surgery, 5th ed. New York, McGraw-Hill, 1989, p 1538.)

Figure 10-8. Lichenstein repair of an inguinal hernia. Mesh is sewn to the transversalis fascia and the inguinal ligament to close the defect. (Adapted with permission from Cameron J: Current Surgical Therapy, 6th ed. St. Louis, Mosby, 1998, p 558.)

3. Laparoscopy

• may also be used to insert synthetic mesh over the hernia defect intraperitoneally via a transabdominal approach or via a preperitoneal approach.
• may be particularly useful in patients with recurrent or bilateral hernias.
• Laparoscopic hernia repair is currently being investigated to compare the benefit of this procedure over other repair techniques.

4. In all hernias, abdominal exploration

• should be considered to assess bowel viability and the need for resection if the presence of necrotic bowel is suspected.

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1. Signs suggestive of necrotic bowelinclude

• leukocytosis.
• the presence of dark or bloody fluid within the peritoneal sac.

1. Signs or symptoms of peritonitis

• represent an absolute indication for abdominal exploration.

1. In rare instances when surgery cannot be performed(e.g., patient refusal), a truss may be strapped in over the defect to attempt to prevent herniation.

• This technique is unreliable and may result in significant scarring, making subsequent repair difficult.

1. Postoperative complications
2. Recurrence of the hernia

• after repair is estimated to occur in 3%–10% of patients.

2. Temporary urinary retention

• with difficulty urinating is common.

3. Wound infection

• occurs in 1%–3% of patients postoperatively.
• is a particularly difficult problem to manage when synthetic mesh is directly involved in the infection.

4. Injury

• to the ilioinguinal, iliohypogastric, and genital branch of the genitofemoral nervesrarely occurs and may result in paresthesias in their distribution of innervation.
• This may present with paresthesias in the scrotum and medial or anterior thigh.

5. Inadvertent injury

• to the structures of the spermatic cord rarely occurs.
• Injury to the vas deferens may be repaired primarily.

6. Seroma and hematoma

III. Other Hernias

1. Femoral hernia (Figure 10-9)
2. Femoral hernias pass under the inguinal ligament, passing medially to the femoral artery, nerve, and vein.
3. These hernias occur much more frequently in women.

• Inguinal hernias, however, are still the most common among women.

3. Characteristically, femoral hernias

• are prone to incarceration and strangulationbecause of the narrow neck of the femoral canal.

4. Signs and symptoms

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1. These hernias are frequently asymptomaticuntil obstruction or strangulation occurs.

• Abdominal pain and manifestations of intestinal obstruction may be present in the absence of localized symptoms in the groin.

1. A characteristic bulge

• in the anteromedial thigh, below the inguinal ligament may be present.

1. Femoral hernias may be confused

• with inguinal hernias if the femoral hernia is deflected over the inguinal ligament through the fossa ovalis femoris.

Figure 10-9. Femoral hernia. (Adapted with permission from Lippincott Williams & Wilkins. Gray and Skandalakis: Atlas of Surgical Anatomy for General Surgeons. Baltimore, Williams & Wilkins, 1985, p 97.)

5. Treatment

. Femoral hernias are generally repaired

• through an inguinal approach.

1. Reduction of the hernia sac

• is often difficult.
• may be facilitated by division of the inguinal ligament, if necessary.

1. A Cooper's ligament or McVay repair

• is necessary to assure adequate closure of the femoral canal.

1. Given the high incidence of strangulation

• a surgeon should have a low threshold for abdominal exploration if strangulation is suspected.

1. Blood in the hernia sac

• is characteristic of strangulation.

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1. Umbilical hernias (see BRS Surgical Specialties, Chapter 3, for umbilical hernias in children
2. In adults

• gradual weakening of the periumbilical fascial tissue may result in hernia formation over time.

2. These hernias occur

• more frequently in womenthan in men.

3. Risk factorsinclude

• multiparity.
• obesity.
• ascites.
• large intra-abdominal tumors.

4. Appropriate treatmentinvolves

• primary surgical repair of the defect.
• insertion of synthetic mesh for large defects.

1. Incisional hernias (ventral hernia)
2. Of patients undergoing abdominal operations

• approximately 5%–10% will develop an incisional hernia.

2. Poor surgical technique

• with inadequate fascial closure or excessive tension is the most common cause of incisional hernia formation.

3. Other risk factorsinclude

• postoperative wound infection.
• increasing age.
• obesity.
• malnutrition.
• pulmonary disease with persistent coughing postoperatively (e.g., smokers).

4. Treatmentinvolves

• careful dissection of the hernia sac with primary fascial repair of small defects.
• insertion of synthetic mesh for large defects to avoid undue tension and potential recurrence.

1. Other rare hernias

• of the abdominal wall are characterized in Table 10-1.

1. Other Lesions of the Abdominal Wall
2. Rectus sheath hematoma

• is characterized by formation of a hematoma within the muscular layers of the abdominal wall.

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Table 10-1. Abdominal Wall Hernias

Hernia Location Characteristics Indirect inguinal Through deep inguinal ring; lateral to inferior epigastric vessels Most common hernia in children and adults Direct inguinal Directly through defect in transversalis fascia; through Hessel-bach's triangle medial to inferior epigastric vessels Borders of Hesselbach's triangle: inferior epigastric vessels, lateral border or rectus, inguinal ligament Pantaloon Inguinal hernia with both direct and indirect components Hernia sac straddles inferior epigastric vessels Femoral Below inguinal ligament medial to femoral vessels Seen more commonly in women; high rate of incarceration and strangulation Umbilical Through defect in umbilical ring Increased risk with obesity, ascites, pregnancy Incisional (ventral) Through fascial defect in previous incision Occurs in 5%–10% of patients with abdominal incision Epigastric Primary defects in linea alba above umbilicus May be multiple; recurrence rate is 10%–20% Spigelian Through linea semilunaris (where aponeurosis join to form the rectus sheath just lateral to the rectus muscles); most commonly at the level of the semicircular line of Douglas. Pain may be present over defect without palpable mass; CT scan or ultrasound may be diagnostic Lumbar Through superior (Grynfeltt's) and inferior (Petit's) lumbar triangles in the posterior abdominal wall Although rare, they occur most commonly in young athletic women Obturator Through obturator canal with obturator nerve and blood vessels Often presents as obstruction; high mortality; pain in medial thigh increased by extension or abduction of leg (Howship-Romberg sign) Internal Through defect in visceral structure (e.g., defect in mesentery) May occur after bowel resection if mesenteric defects not repaired Perineal Through floor of perineum Most frequently occurs following pelvic surgery Interparietal Hernia sac contents migrate between layers of the abdominal wall Rare; high rate of strangulation; ultrasound or CT scan often diagnostic Sciatic Herniation through greater sciatic foramen Rare; high rate of strangulation CT = computed tomography.

1. Hematoma formation

• may be precipitated by mild trauma.
• may occur spontaneouslyin association with disorders of coagulation or platelet function.

2. Abdominal pain

• is the most frequent presenting symptom.

3. Physical examination

• often reveals a very painful abdominal wall mass.

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1. Upon flexion of the rectus abdominis muscles

• the mass becomes more prominent and painful (Fothergill's sign).

1. Intra-abdominal masses

• often disappear upon flexion of the rectus muscles.

1. Ecchymosis

• over the abdomen may also be present.

4. A computed tomography (CT) scanor ultrasound may demonstrate the hematoma.
5. The hematoma will usually resolve without surgical intervention.
6. Evacuation of the clotwith adequate hemostasis

• may be performed in patients with severe, persistent pain.

1. Tumors of the abdominal wall
2. Most tumors of the abdominal wall are benign.
3. Examplesinclude lipomas, hemangiomas, and fibromas.

• These may be resected if symptomatic.

3. Desmoid tumors

• are also benign lesions, although they may resemble low-grade fibrosarcomas.
• may infiltrate adjacent tissues but never metastasize.
• Effective treatment of desmoid tumors involves resection or radiation therapy.

4. Malignant lesions of the abdominal wall

• are most often metastatic lesions from an intra-abdominal source.

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Review Test

Directions: Each of the numbered items or incomplete statements in this section is followed by answers or by completions of the statement. Select the ONE lettered answer or completion that is BEST in each case.

1. A 35-year-old man presents to the office with complaints of a recurrent right tender groin mass. He states that he most frequently notices the mass after working all day but that it usually goes away by morning. On physical examination, there is a palpable mass noted upon insertion of the index finger into the scrotal region. The mass is soft and becomes more prominent when the patient performs a Val-salva maneuver (e.g., cough). In this patient, this mass passes through

(A) The deep inguinal ring

(B) Hesselbach's triangle

(C) The femoral canal

(D) The obturator foramen

(E) The superficial inguinal ring

1–E. It is very difficult to differentiate a direct hernia (through Hesselbach's triangle) from an indirect (through the deep inguinal ring) hernia on physical examination. Identification of a hernia sac in the scrotum merely confirms that an inguinal hernia has passed through the superficial inguinal ring into the scrotum. Hernias through the femoral canal or obturator canal would not present with a scrotal mass.

2. A 35-year-old man undergoes an uneventful elective right inguinal Lichtenstein hernia repair. The patient presents 10 days later with a complaint of severe pain over the incision site. On physical examination, the incision site is noted to be erythematous and there is significant purulent drainage coming from the wound. There is also a significant reducible soft mass in the wound suggestive of a recurrence of the hernia. Which of the following is the most appropriate treatment strategy for this patient?

(A) Wound exploration, mesh removal, and repair of hernia with new mesh

(B) Discharge, administration of antibiotics, and close follow-up

(C) Wound exploration, mesh removal, and perform a McVay repair

(D) Discharge and wet to dry dressing changes 3 times a day

(E) Insertion of a drain, administration of antibiotics, and close observation

2–C. A wound infection with an early recurrence of the hernia in the presence of synthetic material requires prompt exploration with drainage and removal of the infected mesh. Repair of the hernia with new mesh would not be indicated in the presence of an infected wound, thus a repair without mesh, such as the McVay repair, would be indicated in this situation. Discharging the patient would be inappropriate in this setting. Insertion of a drain and antibiotic therapy would not be adequate treatment for an infection in this setting.

3. A 65-year-old man with no previous abdominal surgery presents with severe abdominal pain over the right lower quadrant (RLQ). His past medical history is significant for a previous aortic valve repair and the patient is on chronic coumarin (Coumadin) anticoagulant therapy. On physical examination there is an exquisitely tender mass noted in the RLQ just lateral to the umbilicus. When the patient attempts to sit up the mass remains palpable and the pain associated with the mass increases. Of the following, which is most appropriate in the management of this patient?

(A) Incision and drainage with wound packing

(B) Immediate exploratory laparotomy

(C) Local exploration and biopsy of the mass

(D) Performance of an abdominal computed tomography (CT) scan

(E) Colonoscopy to rule out colon cancer

3–D. Increasing pain and persistence of the mass with flexion of the rectus abdominis muscles (Fothergill's sign) is a characteristic finding of a rectus sheath hematoma. Coumarin (Coumadin) anticoagulant therapy is also a significant risk factor for the development of a rectus sheath hematoma. Despite these suggestive findings, an abdominal computed tomography (CT) scan would help to rule out other potential causes such as an abdominal wall hernia, tumor, or abscess. Local exploration or incision and drainage is not necessary before performing the CT scan. Because the mass appears to be within the abdominal wall, an exploratory laparotomy is not indicated at this time, although if a hernia is identified on CT scan, exploration may be indicated. This lesion is not likely to be associated with a colon cancer and thus colonoscopy is not indicated.

4. A 59-year-old, obese woman presents to the emergency room with a painful right groin mass below the inguinal ligament. Aggressive attempts to reduce the mass are unsuccessful. Intraoperatively, the patient is confirmed to have an incarcerated femoral hernia although the viability of the bowel appears intact. Attempted intraoperative reduction of the hernia sac is unsuccessful as well. Which of the following is the most appropriate next step in the management of this patient?

(A) Resection of the herniated bowel and primary reanastomosis

(B) Division of the inguinal ligament with reduction of the hernia contents

(C) Performance of an enterotomy and decompression of the herniated bowel

(D) Performance of a laparotomy with traction of the herniated bowel intraperitoneally

(E) Performance of a McVay repair despite the inability to reduce the hernia sac

4–B. Because of the narrow neck of the femoral canal, femoral hernias frequently present with incarceration. Some femoral hernias are even difficult to reduce intraoperatively, in which case the inguinal ligament can be divided and repaired following reduction of the hernia sac. If the bowel is viable, resection is not indicated. Performance of an enterotomy is not indicated because of the risk of contamination. A laparotomy would not be necessary in this situation and repair of the hernia without reduction of the hernia sac would be impossible.

5. After a routine left inguinal hernia repair, a 45-year-old man presents to the office complaining of numbness over a portion of the left side of his scrotum and over the anteromedial portion of his left thigh. Very anxious about these findings, the patient also asks if this is associated with sexual dysfunction. Which of the following is an appropriate explanation with regards to the patient's inquiry?

(A) There is a significant risk of erectile dysfunction associated with this complication

(B) Erectile function remains unaffected although the patient may be sterile

(C) The hernia has probably recurred and will require reoperation

(D) This probably represents an inadvertent injury to the iliohypogastric nerve

(E) This probably represents an inadvertent injury to the ilioinguinal nerve

5–E. Although uncommon, injury of the iliohypogastric, ilioinguinal, and genital branch of the genitofemoral nerve may occur during inguinal hernia repairs. As in this patient, ilioinguinal nerve transection generally presents with paresthesias and numbness in the scrotum and anteromedial thigh region. This nerve provides cutaneous sensory fibers and injury would not be associated with erectile dysfunction or sterility. These symptoms are also not consistent with recurrence of the hernia. Injury to the iliohypogastric nerve generally presents with paresthesias in the region of the lower abdomen below the umbilicus and the anterolateral thigh.

Directions: Each set of matching questions in this section consists of a list of four to twenty-six lettered options followed by several numbered items. For each numbered item, select the appropriate lettered option(s). Each lettered option may be selected once, more than once, or not at all.

Questions 6–12

1. Indirect inguinal hernia
2. Direct inguinal hernia
3. Umbilical hernia
4. Spigelian hernia
5. Pantaloon hernia
6. Littré's hernia
7. Richter's hernia
8. Obturator hernia
9. Incisional (ventral) hernia
10. Femoral hernia
11. Epigastric hernia
12. Lumbar hernia

Choose the hernia(s) associated with each patient scenario.

6. A 55-year-old woman with no history of previous abdominal surgery presents with signs and symptoms suggestive of a small bowel obstruction. There are no groin masses noted upon physical examination. The patient notes pain in the medial thigh, which worsens upon extension of the leg. (SELECT 1 HERNIA)

6–H. Any patient that presents with a small bowel obstruction without previous abdominal surgery should be suspected of having a hernia. Although rare, an obturator hernia may present as a small bowel obstruction without other significant findings. Pain noted in the medial thigh that worsens upon extension or abduction of the leg is a characteristic finding (Howship-Romberg sign) of an obturator hernia.

7. A 35-year-old man presents with a tender right scrotal mass. Upon physical examination, a soft mass is palpated at the level of the external inguinal ring. (SELECT 3 HERNIAS)

7–A, B, E. Palpation of a hernia sac at the level of the external inguinal ring suggests the presence of either a direct or an indirect hernia, or both (pantaloon hernia). Simple palpation of a hernia sac at this level does not differentiate between these hernias.

8. A 34-year-old woman with no previous abdominal surgery presents with complaints of a tender mass in the midline of the abdomen above the level of the umbilicus. Upon physical examination, there are 2 small midline soft masses noted above the level of the umbilicus. (SELECT 1 HERNIA)

8–K. In the absence of previous abdominal surgery, hernias in the midline above the level of the umbilicus probably represent epigastric hernias. These hernias occur through defects in the linea alba and may be multiple.

9. A 42-year-old woman presents with signs and symptoms suggestive of a small bowel obstruction. She has had no previous abdominal surgeries. There are no palpable abdominal masses or masses in the groin region, however there is a localized point of tenderness over a small region inferior to the umbilicus and lateral to the rectus abdominis muscle. (SELECT 1 HERNIA)

9–D. Spigelian hernias occur through defects in the linea semilunaris, where the aponeuroses of the abdominal muscles converge to form the rectus sheath just lateral to the rectus abdominis muscles. The most common site is at the level of the semicircular line of Douglas just below the umbilicus where the posterior rectus sheath ends. Because the hernia sac may track between the layers of the abdominal muscles, a mass may not be palpable. There may, however, be pain noted over the site of herniation. Ultrasound or computed tomography (CT) scan may be diagnostic when these lesions are suspected.

10. A 42-year-old woman with a previous open cholecystectomy presents to the emergency room with signs and symptoms suggestive of a small bowel obstruction. On physical examination, there is a palpable soft mass noted just below the right inguinal ligament. (SELECT 1 HERNIA)

10–J. Signs and symptoms of a small bowel obstruction with a hernia palpated below the level of the inguinal ligament should suggest the presence of an incarcerated femoral hernia. The defect associated with a femoral hernia is small, therefore these hernias are prone to incarceration and strangulation.

11. A 42-year-old man presents with a very painful right groin mass. The mass is reduced preoperatively. Intraoperatively, the hernia sac is noted to be lateral to Hesselbach's triangle and a McVay hernia repair is performed. Of note, there was bloody fluid noted within the hernia sac. (SELECT 3 HERNIAS)

11–A, F, G. Indirect inguinal hernias occur lateral to the inferior epigastric vessels through the deep inguinal ring. Bloody fluid noted within the hernia sac suggests the presence of strangulated bowel. Two types of hernias that may present with strangulation without previous signs or symptoms of bowel obstruction include Richter's hernia and Littré's hernia. A Richter's hernia is characterized by partial herniation of the antimesenteric border of the intestinal wall. Littré's hernia is characterized by herniation of a Meckel's diverticulum. A significant risk associated with these two hernias is reduction of a strangulated portion of intestine.

12. A 65-year-old, obese man has had a previous colon resection for colon cancer through a midline abdominal incision. He now presents with a nontender soft mass in the midline approximately 4 cm above the umbilicus. (SELECT 1 HERNIA)

12–I. Identification of a hernia sac at the site of a previous incision probably represents a ventral or incisional hernia. These hernias occur in 5%–10% of patients undergoing abdominal surgery. Umbilical hernias generally occur directly around the umbilicus.