Inguinofemoral Area

Inguinal Canal

Anatomy of the Inguinal Canal in Infants and Children

There are readily apparent differences between the inguinal canals of infants and adults. In infants, the canal is short (1 to 1.5 cm), and the internal and external rings are nearly superimposed upon one another. Scarpa's fascia is so well developed that the surgeon may mistake it for the aponeurosis of the external oblique muscle, resulting in treating a superficial ectopic testicle as an inguinal cryptorchidism. There also may be a layer of fat between the fascia and the aponeurosis. We remind surgeons of the statement of White that the external oblique fascia has not been reached as long as fat is encountered.

In a newborn with an indirect inguinal hernia, there is nothing wrong with the posterior wall of the inguinal canal. Removal of the sac, therefore, is the only justifiable procedure. However, it is extremely difficult to estimate the weakness of the newborn's posterior inguinal wall by palpation. If a defect is suspected, a few interrupted permanent sutures might be used to perform the repair.

Adult Anatomy of the Inguinal Canal

The inguinal canal in the adult is an oblique rift in the lower part of the anterior abdominal wall. It measures approximately 4 cm in length. It is located 2 to 4 cm above the inguinal ligament, between the opening of the external (superficial) and internal (deep) inguinal rings.

The boundaries of the inguinal canal are as follows:

Anterior: The anterior boundary is the aponeurosis of the external oblique muscle and, more laterally, the internal oblique muscle. Remember, there are no external oblique muscle fibers in the inguinal area, only aponeurotic fibers.

Posterior: In about ¾ of subjects, the posterior wall (floor) is formed laterally by the aponeurosis of the transversus abdominis muscle and the transversalis fascia; in the remainder, the posterior wall is transversalis fascia only. Medially the posterior wall is reinforced by the internal oblique aponeurosis.

Superior: The roof of the canal is formed by the arched fibers of the lower edge (roof) of the internal oblique muscle and by the transversus abdominis muscle and aponeurosis.

Inferior: The wall of the canal is formed by the inguinal ligament (Poupart's) and the lacunar ligament (Gimbernat's).

The boundaries of the rings are as follows:

External ring (Fig. 1-1): There is a triangular opening of the aponeurosis of the external oblique, the base being part of the pubic crest with the margins formed by two crura, superior (medial) and inferior (lateral). The superior crura is formed by the aponeurosis of the external oblique itself; the inferior crura is formed by the inguinal ligament. To be more specific, the medial crus is attached to the lateral border of the rectus sheath and to the tendon of the rectus abdominis muscle in a very peculiar pathway. The lateral crus is attached to the pubic tubercle.

Fig(1-1)Highly diagrammatic representation of the external inguinal ring. (Modified from Skandalakis JE, Skandalakis LJ, Colborn GL, Androulakis J, McClusky DA III, Skandalakis

PN. The surgical anatomy of the hernial rings. In: Baker RJ, Fischer JE (eds). Mastery of Surgery (4th ed). Philadelphia: Lippincott Williams & Wilkins, 2001; with permission.)

Internal ring (Fig. 1-2): The boundaries of this ring, which is an inverted "V" -or "U"-shaped normal defect in the transversalis fascia, are not so simple. The arms of the ∧, anterior and posterior, are a special thickening of the transversalis fascia, forming a sling. The inferior border is formed by another thickening of the transversalis fascia —the iliopubic tract— which is not always very aponeurotic.

The internal inguinal ring is an opening of the transversalis fascia corresponding to the middle of the inguinal ligament (see section on sphincteric action under the physiology of the inguinal canal).

Fig(1-2)Surgical anatomy of the internal inguinal ring. (Modified from Skandalakis

JE, Skandalakis LJ, Colborn GL, Androulakis J, McClusky DA III, Skandalakis PN. The surgical anatomy of the hernial rings. In: Baker RJ, Fischer JE (eds). Mastery of

Surgery (4th ed). Philadelphia: Lippincott Williams & Wilkins, 2001; with permission.)

The inguinal canal contains, in males, the spermatic cord, or in females, the round ligament of the uterus.

The anterior wall of the inguinal canal is formed by the aponeurosis of the external oblique muscle and by participation of the internal oblique muscle more laterally. As a point of reference, the internal oblique muscle in the inguinal area is muscular, not aponeurotic. The superior wall ("roof") of the inguinal canal is formed by the arching lower borders of the internal oblique and transversus abdominis muscles and their aponeuroses. The inferior wall of the inguinal canal is formed by the inguinal ligament and the lacunar ligament. The posterior wall is formed primarily by fusion of the aponeurosis of the transversus abdominis muscle and the transversalis fascia in three-fourths of subjects and by only the transversalis fascia in the remaining one-fourth.

From both anatomic and surgical standpoints, the posterior wall (floor) is the most important wall of the inguinal canal. Medially the posterior wall is reinforced by the internal oblique aponeurosis.

Fig(1-3)Piriform fossa of Fruchaud, popularized by Madden. (Modified from Colborn GL,

Skandalakis JE. Importance of the iliopubic, Cooper's and Gimbernat's ligaments. Probl Gen

Surg 1995;12:35-40; with permission.)

According to Madden JL 1999, the "piriform fossa" forms part of the posterior wall ("floor") of the inguinal canal. This region is a semi-ovoid space filled with fibrofatty tissue, located at the medial part of the floor. The piriform fossa is bounded as follows (Fig. 1-3):

Superior: Iliopubic tract (which inserts into Cooper's ligament)

Inferior: Shelving edge of inguinal ligament

Lateral: Medial wall of femoral sheath

Medial: Ligament of Gimbernat

"Floor": Ligament of Gimbernat

Wantz noted that Fruchaud did not characterize hernias by their clinical presentation; instead, Fruchaud believed that all hernias of the groin begin within the groin, in an area he named the myopectineal orifice. This area in the groin is bounded as follows:

Superior: Arch of internal oblique muscle and transversus abdominis muscle

Lateral: Iliopsoas muscle

Medial: Lateral border of rectus muscle and its anterior lamina

Inferior: Pubic pectin

The inguinal ligament spans and divides this framework. The area is traversed by the spermatic cord and femoral vessels and is covered on its inner surface solely by the transversalis fascia.

Spermatic Cord

The spermatic cord is presented in depth in the chapter on the male genital system. We include here a brief review of the surgical anatomy of this important entity in the inguinal canal.

The spermatic cord consists of a matrix of connective tissue continuous proximally with extraperitoneal connective tissue. It contains the ductus deferens, three arteries, three veins, the pampiniform plexus, and two nerves, concentrically invested by three layers of tissue. One other nerve, the ilioingual nerve, usually lies just lateral to the major layers of the cord within the inguinal canal.

The elements of the spermatic cord relate to each other as follows: 1) anterior is the pampiniform plexus, and 2) posterior are the ductus deferens and the remnant of the processus vaginalis or hernia sac. These anatomic entities, as well as other contained structures, are covered by the spermatic fasciae. The spermatic cord, on the way to the scrotum, lies deep to the fasciae of Camper and Scarpa. The components of the cord are noted in Table 9-6. The key to remember is "three": three layers of fasciae, three arteries, three veins, three nerves, as well as multiple lymphatics and one duct.

Table 9-6. the Spermatic Cord and Its Covering

Three fasciae:

External spermatic (from external oblique fascia)

Cremasteric (from internal oblique muscle and fascia)

Internal spermatic (from transversalis fascia)

Three arteries:

Testicular artery

Cremasteric artery

Deferential artery

Three veins:

Pampiniform plexus and testicular vein

Cremasteric vein

Deferential vein

Three nerves:

Genital branch of genitofemoral nerve

Ilioinguinal nerve

Sympathetic nerves (testicular plexus)

Lymphatics

Source: Skandalakis JE, Colborn GL, Pemberton LB, Skandalakis LJ, Gray SW. The surgical anatomy of the inguinal area — Part 2. Contemp Surg 38(2):28-38, 1991; with permission.

Superficial Fascia

The superficial fascia (Fig.1-5) is divided into a superficial fatty part (Camper's fascia) and a deep membranous part (Scarpa's fascia). The adipose layer continues downward and laterally into the thigh, gluteal region, and perineum and upward over the anterior abdominal wall and thoracic region. The membranous layer of Scarpa is continuous upward with the fatty layer in the pectoral region, forming the anterior boundary of the retromammary space. Inferiorly, it attaches to the fascia lata of the thigh below the inguinal crease. It is also attached superolaterally to the iliac crest. According to Brantigan,57 Scarpa's fascia does not adhere to the symphysis pubis.

Fig(1-5)Superficial fascia (dartos): composed of Scarpa's fascia (membranous) and muscle, and Camper's fascia, which is fatty. Gallaudet's fascia is a continuation of Buck's fascia.

The adipose layer and the membranous layer combine in the pubic region, losing much of the fatty content. Together, they form the fundiform ligament, a relatively loose fibrous structure that attaches to the base of the penis (or the clitoris). There, receiving input of smooth muscle fibers, the superficial fascia continues as the dartos tunic of the penis and scrotum (or as the clitoris), where it serves as a superficial fascial layer.

In the perineum, the membranous layer is renamed Colles' fascia (Fig.1-5). It attaches laterally to the ischiopubic rami and posteriorly to the base of the urogenital diaphragm. In this way, a space called the superficial perineal cleft is limited posteriorly and laterally. This cleft is bounded deeply by the muscle fascia (of Gallaudet) of the superficial perineal pouch. Extravasation of fluid from this area

occurs in an anterior direction, passing anterosuperiorly around the genitalia to reach the anterior abdominal wall.

Deep Fascia

The deep muscular fascia of the anterior wall (known as the fascia innominata or Gallaudet's fascia) is continuous over the shaft of the penis or clitoris, forming their deep fascial investment. There they are known as Buck's fascia. In the perineum, this tough fascial layer is continuous over the superficial musculature, again referred to as fascia of Gallaudet or as inferior (external) perineal fascia.

Hollinshead considered Buck's fascia to be an independent layer. This fascial layer, together with tough connective tissue from the lowest extent of the rectus sheath and the front of the pubic bone, forms the suspensory ligament of the penis or clitoris. It then proceeds more distally as the deep fascia of those structures.

Inguinal Ligament

The lower edge of the external oblique aponeurosis extends from the anterior superior iliac spine to the pubic tubercle. This is the inguinal ligament (ligament of Poupart). The ligament is related laterally to the iliopsoas muscle and its fascia. It is related medially to the femoral vessels. The ligament is also related indirectly to the femoral ring, to the iliopubic tract, and to other thickenings of the transversalis fascia.

Doyle drew attention to the probability that it was Fallopius, not Poupart, who first described this aponeurotic band as a ligament, noting that none of the biographers of Poupart attributed this discovery to him. Doyle added that Poupart was far better known for his writings on ghostly apparitions, dragonflies, and hermaphroditic insects.

Gimbernat's ligament and the reflected inguinal ligament are formed before the inguinal ligament reaches the pubic tubercle (see the section on the ligament of Gimbernat (lacunar ligament) below).

Aponeurosis and Fascia of the External Oblique Muscle as Related to the Groin

The external oblique muscle is not present in the groin area. Only its aponeurosis extends downward and medially, to pass anterior to the rectus muscle. Here, it also joins the aponeurosis of the internal oblique muscle and that of the transversus abdominis to form the anterior layer of the rectus sheath. Between this attachment and an inferior attachment to the pubic bone lies a triangular hiatus (superficial inguinal ring) through which passes the spermatic cord or the round ligament. The innominate fascial covering of the external oblique muscle travels further downward and forms the external spermatic fascia of the spermatic cord.

Conjoined Area (Tendon)

Buried among the names of structures real or imaginary in the inguinal region is the term conjoined tendon. If one consults a medical dictionary, one finds that

anatomists decided in 1895 that it should be called the falx inguinalis. At the time of this decision, inguinal anatomy was still developing.

About 1900, the term conjoined tendon entered the literature. The earliest use has not been found. The term appears in the 1902 edition of Gerrish's Textbook of Anatomy by American Authors. In 1950, 1960, and again in 1985,Nomina Anatomica's authors admitted that usage favored conjoined tendon rather than falx inguinalis. They agreed that tendo conjunctivus would be considered an "official alternative."

The conjoined tendon is, by definition, the fusion of lower fibers of the internal oblique aponeurosis with similar fibers from the aponeurosis of the transversus abdominis where they insert on the pubic tubercle and superior ramus of the pubis.

We have tried to avoid the controversy about conjoined tendon and conjoined area , but many years of teaching anatomy and practicing surgery require us to take a position based on the following points:

"The conjoined tendon does not exist." (McVay)

"The distinction between falx inguinalis and conjoined tendon is one of anatomic nicety and admittedly of little practical significance in the operating room provided that the distinction is understood." (Condon)

The term conjoined area can be applied correctly to that region that contains the ligament of Henle, the transversus abdominis aponeurosis, the inferomedial fibers of the internal oblique muscle or aponeurosis, the reflected inguinal ligament, and the lateral border of the rectus sheath.

Ligament of Gimbernat (Lacunar Ligament)

The ligament of Gimbernat (Fig. 1-6) is a triangular extension of the inguinal ligament before its insertion upon the pubic tubercle. It is inserted at the pecten pubis, and its lateral end meets the proximal end of the ligament of Cooper. Condon asserted "... it [the ligament of Gimbernat] never forms the medial border of the normal femoral canal." Similarly, Doyle stated emphatically that the lacunar ligament is situated 4-15 mm medial to the femoral ring, and thus has no part in forming its medial border. The results of hundreds of dissections that the senior author of this chapter has done, whether on fixed or unfixed material, leave no doubt in his mind as to the validity of this point of view. Other investigators, however, hold the view that the lacunar ligament forms the medial border of the canal.

Fig(1-6)Inguinal ligament, lacunar ligament (Gimbernat's), pectineal ligament (Cooper's), neuromuscular compartment, vascular compartment, compartment of femoral canal. (Modified from Skandalakis LJ, Gadacz TR, Mansberger AR Jr, Mitchell WE Jr, Colborn GL, Skandalakis JE. Modern Hernia Repair: The Embryological and Anatomical Basis of Surgery. New York: Parthenon, 1996; with permission.)

Cooper's Ligament (Pectineal Ligament)

Our experience has proven that the ligament of Cooper includes elements of the following anatomic entities:

Periosteum

Lateral part of the lacunar ligament (fused to the periosteum)

Fibers originating from the upper part of the pectineal fascia in such a way that the fascia is located under the periosteum and the lacunar ligament. Perhaps one can say that this is an area of origin of muscle (pectineus), as well as insertion.

Aponeurotic fibers from the insertion of the transversus abdominis and the iliopubic tract

Insertion of the transversalis fascia

(Occasionally) fibers from the insertion of the rectus tendon

(Occasionally) fibers from the insertion of the internal oblique muscle

Fusion of the outer lamina of extraperitoneal connective tissue

For all practical purposes, Cooper's ligament consists of:

Periosteum of the pectineal line

Insertion of the iliopubic tract from above to the periosteum

Insertion of the lacunar ligament from below to the periosteum

Origin of the pectineus tendon from below (Figs. 9-29, 9-30, 9-31.)

Dare we anatomists and surgeons ask for greater precision than can reasonably be determined? Is the word "ligament" the correct one? If the ligament is the periosteum, then this "ligament" is the reinforcement by thick fibrous tissue of several anatomic entities. What about the concept that the Cooper's ligament belongs to the external oblique aponeurosis complex? Do modern beliefs about the anterior and posterior laminae of the abdominal wall and inguinal canal and, therefore, the repair of inguinal hernias, need to change (see? We doubt it.

Remember

The iliopubic tract is inserted into the ligament of Cooper from above (superiorly).

The ligament of Gimbernat is inserted partially upon the ligament of Cooper from below (inferiorly).

The pectineus tendon originates from the ligament of Cooper from below (inferiorly). Its medial part is covered by the ligament of Gimbernat.

Arch of the Transversus Abdominis

The arch of the transversus abdominis muscle becomes less muscular and more aponeurotic (transversus aponeurosis) as it approaches the rectus sheath. Close to the internal ring, it is covered by the much more muscular arch of the internal oblique muscle, but it is rarely covered in the lower medial portion of the inguinal region. Remember that in the inguinal canal region the internal oblique is muscular. The transversus abdominis is aponeurotic.

Ligament of Henle (Falx Inguinalis)

The ligament of Henle was originally termed falx inguinalis. We prefer the former term because the falx has become confused with the conjoined tendon (previously described in this chapter). The ligament of Henle is the lateral vertical expansion of the rectus sheath that inserts on the pecten of the pubis. Since this ligament is present in one-third to one-half of patients and is fused with the

transversus aponeurosis and fascia, it may be seen occasionally in the surgical field, and the surgeon's needle may penetrate it once or twice in the course of hernia repair.

Interfoveolar Ligament (Hesselbach's Ligament)

The interfoveolar ligament is a thickening of the transversalis fascia at the medial side of the internal inguinal ring. It lies in front of the inferior epigastric vessels like a spider web. It is not a true ligament, and when well-developed, one has the impression that it is only a lateral condensation of the ligament of Henle.

Reflected Inguinal Ligament (Colles' Ligament)

The reflected inguinal ligament consists of aponeurotic fibers from the inferior crus of the external inguinal ring that extend to the linea alba. This is the posterior crus of French anatomists.

Iliopubic Tract

Alexander Thomson described the iliopubic tract in 1836.80 Some historians believe that Hesselbach81 provided a description in 1814. The tract is known by several names: ligament of Thomson, deep crural arch, deep femoral arch, anterior femoral sheath, and (in French) bandelette iliopubienne.

The iliopubic tract is an aponeurotic band that begins near the anterior superior iliac spine. It extends medially to attach to Cooper's ligament. It forms the inferior margin of the deep musculoaponeurotic layer made up of the transversus abdominis muscle and aponeurosis and the transversalis fascia (see Fig. 1-7).

Fig(1-7)Iliopubic tract and its relations to genital branch of genitofemoral nerve. (Modified from Colborn GL, Skandalakis JE. Importance of the iliopubic, Cooper's and Gimbernat's ligaments. Probl

Gen Surg 1995;12:35-40; with permission.)

Laterally, the tract is attached to the iliacus and psoas fasciae. It continues more laterally to the anterior superior spine of the ilium. It passes medially to form the lower border of the internal inguinal ring. Together with the transversalis fascia, the tract crosses the femoral vessels to form the anterior margin of the femoral sheath. The tract curves around the medial surface of the femoral sheath to attach to the pectineal ligament. It provides the medial border of the femoral ring and femoral canal. Its lower margin is attached to the inferior edge of the inguinal ligament along a variably dense line of fusion in the region of the inguinal canal.

Transversalis Fascia Crura

The transversalis fascia crura is a thickening of the transversalis fascia. It forms an incomplete ring in the shape of an inverted "V" or "U" at the deep inguinal ring. There are two crura. The anterior (superior) long crus is attached to the transversus abdominis muscle or its aponeurosis. The posterior (inferior) short crus is attached to the iliopubic tract.

REMEMBER:

The cremaster vessels and the genital branch of the genitofemoral nerve are located very close to the iliopubic tract at the posterior wall of the inguinal canal.

Iliopectineal Arch

The iliopectineal arch is a band of fascia and aponeurotic fibers marking the attachment of the external oblique aponeurosis to the fasciae of the iliacus and psoas muscles. It attaches laterally to the anterior superior iliac spine and medially to the iliopubic (iliopectineal) eminence.

Fig(1-8)Iliopectineal arch. (Modified from Nyhus LM. An anatomical reappraisal of the posterior inguinal wall. Surg Clin North Am 1964;44:1305; with permission.)

The iliopectineal arch (Fig. 1-8) divides the space beneath the inguinal ligament into two separate spaces: the lacuna musculorum of the iliopsoas muscle laterally, and the lacuna vasculorum of the external iliac vessels medially. In the region of the iliopubic eminence, this fascial band is further strengthened by profuse contributions from the fascia of the pectineus muscle and other entities and forms a fascial complex called the iliopectineal fascia. The surgeon never directly uses this fascia, but it is important as a common junction of several structures of the lateral groin. These structures are:

The insertion of fibers of the external oblique aponeurosis

The insertion of fibers of the inguinal ligament

The origin of part of the internal oblique muscle

The origin of part of the transversus abdominis muscle

Part of the lateral attachment of the iliopubic tract. It contributes also to the lateral wall of the femoral sheath.

Transversalis Fascia as Related to the Inguinal Area

The term "transversalis fascia" was applied in the past to the deep fascia covering the internal surface of the transversus abdominis muscle. Now, it applies to the entire connective tissue sheet lining the musculature of the abdominal cavity. In some areas, this fascial layer is given a specific name, such as "iliacus" or "psoas" fascia, where it covers those specific muscles.

The transversalis fascia varies in nature. It is thin and closely adherent in the portion covering the transversus abdominis aponeurosis, but in other areas it is thick and discrete.70 By itself, however, the transversalis fascia is a weak layer, useless for hernia repair. Yet, when fused with the transversus abdominis aponeurosis, it forms "good stuff" for repair.

Spaces and Fossae

Space of Bogros

Fat and other connective tissue, either thick or thin, lies within a space between the peritoneum and the posterior lamina of the transversalis fascia that is called the space of Bogros (Fig. 1-9). Fibrous bands are present, and lipomata similar to those in the spermatic cord occasionally are found. The preperitoneal space is exposed by the reflection of parietal peritoneum toward the iliac fossa before it reaches the pubic bone.11

According to Stoppa (personal communication, René Stoppa to John E. Skandalakis, 1992), Bogros was a French anatomist and surgeon who wrote a thesis in 1823 about the surgical anatomy of the iliac region. Bogros described a triangular space with the following boundaries:

Lateral: Iliac fascia

Anterior: Transversalis fascia

Medial: Parietal peritoneum

Stoppa wisely stated that this cleavable interparietoperitoneal space is considered to be the lower prolongation of the great posterior para-urinary space.

Hureau et al.86,87 after radiologic and anatomic studies of this area, considered the composition of the posterior para-urinary area to be the following:

Fig(1-9)Highly diagrammatic representation of the layers of the abdominal wall and inguinal area. 1, External oblique fascia (fascia of Gallaudet); 2, External oblique aponeurosis; 3, Internal oblique

muscle; 4, Transversus abdominis muscle and its aponeurosis; 5, Transversalis fascia anterior lamina (third layer); 6, External spermatic fascia; 7, Cooper's ligament; 8, Pubic bone; 9, Pectineus muscle; 10, Possible union of transversalis fascia laminae; 11, Transversalis fascia posterior lamina (second

layer); 12, Vessels (second space); 13, Peritoneum (first layer); 14, Space of Bogros (first space); 15, Preperitoneal fat; 16, Transversus abdominis aponeurosis and anterior lamina of transversalis fascia; 17, Femoral artery; 18, Femoral vein. (Modified from Skandalakis JE, Colborn GL, Androulakis JA,

Skandalakis LJ, Pemberton LB. Embryologic and anatomic basis of inguinal herniorrhaphy. Surg Clin North Am 1993;73:799-836. Drawn with R.C. Read; with permission.)

Anterior: Gerota's fat contained within the fascia

Posterior: A cellular space that most likely incorporates the space of Bogros in the internal iliac fossa

According to Bendavid,88 the space of Bogros is a lateral extension of the retropubic space of Retzius. It may be explored by incising the transversalis fascia from the internal ring to the pubic crest. Bendavid also reported that a venous network is most likely located at the lower and anterior part of the space of Bogros, with fixation of the network to the anterior wall. The Bendavid "venous circle," located at the subinguinal space of Bogros, is a variable circular venous network composed of the deep inferior epigastric vein, the iliopubic vein, the rectusial vein, the retropubic vein, and the communicating rectusioepigastric vein (Figs. 9-38, 9-39). Bendavid advised familiarity with this venous circle, particularly for those surgeons using prosthetic material.

The fascinating and instructive essay by Bogros on the surgical anatomy of the inguinal region contains much food for thought, in addition to observations which

we believe to be understandable misinterpretations of regional anatomy. Among the informative descriptions provided by Bogros is one detailing the origin, course, and branching pattern of the deep circumflex iliac artery (called the anterior iliac in the thesis), a vessel which is frequently overlooked in conventional descriptions of the anatomy of the inguinal region pertaining to inguinal herniorrhaphy. Much of the artery lies deep to the iliopubic tract, and is crossed there by several nerves of significance.

Bogros speaks of the extraperitoneal space inferiorly within the abdominal cavity where the peritoneum reflects from the anterior abdominal wall to the iliac fossa. There, at a space some 12-14 mm wide, he notes the external iliac and inferior epigastric vessels are devoid of serosal covering, and are accessible to ligation without division of the peritoneum.

It is our assumption that the extraperitoneal space described by Bogros, in which the inferior epigastric and external iliac vessels can be secured and ligated, is the space or is coextensive with the space now being referred to as the "space of Bogros." As noted by Dr. Bendavid, the preperitoneal space of Bogros is continuous with the retropubic space of Retzius and is entered in "external" herniorrhaphies when the posterior lamina of the transversalis fascia is divided and the inferior epigastric vessels are exposed, surrounded by adipose tissue.

Bogros stated that there is a "layer of cellular tissue" between the transversalis fascia and the epigastric vessels and, further, that there is, posteriorly, a thicker layer of similar tissue which separates the vessels from the peritoneum. The more anterior layer of extraperitoneal fascia has been noted by others, recently also by Read. We have observed that the extraperitoneal layer of connective tissue often splits quite distinctly lateral to the inferior epigastric vessels, with one lamina passing anterior to the inferior epigastric artery and vein and the other lamina passing posterior to those vessels. Perhaps Bogros was familiar with the work of Cooper about the bilaminar transversalis fascia in this area.

As we see it, the more anterior lamina of the extraperitoneal connective tissue varies considerably in its density, and in the amount of adipose tissue with which it may be associated. When one divides this layer of tissue, one can then enter the retropubic space of Retzius. The deeper lamina is more complex. Just medial to the inferior epigastric vessels, it appears to form the lateral edge of the vesicoumbilical fascia,

which contains the umbilical artery, and the urachus. This lamina also seems to more or less clearly form a mesentery-like structure for the round ligament or ductus deferens. The inguinal representation of the extraperitoneal layers of connective tissue is but one expression of the complex regional specializations of this matrix, illustrated also by the renal fasciae. Fused with the aponeurotic origin of the transversus abdominis from the fascia iliaca, the extraperitoneal connective tissue contributes heavily also to the characteristic appearance of the iliopubic tract.

Bogros describes the course of the inferior epigastric artery clearly, observing that it courses first inferiorly, and then curves back sharply upward to reach, and ascend upon, the anterior abdominal wall. In that the inferior epigastric artery can arise from the external iliac artery 0-5 cm proximal to the origin of the deep circumflex iliac and the passage of the main artery beneath the inguinal ligament, according to Bogros, does the point of origin of the inferior epigastric from the external iliac affect the length of the above-noted space, wherein the artery is devoid of peritoneal covering? Bogros sheds no light on this interesting and pertinent question.

The description of the branches and distribution of the inferior epigastric vessels, as detailed by Bogros, is intriguing in its details. He observes that the first branch passes medially to supply the tissues within the femoral canal, notably lymphatic in nature, and then continues to anastomose with, or replace, the obturator artery. These important observations and the fact that such vessels can easily suffer injury in herniorrhaphies have been mentioned often in recent literature. Bogros notes that the second branch of the inferior epigastric, the retropubic artery, can likewise be the source of an aberrant obturator artery. In herniorrhaphy, some authors recommend division of the ligament of Gimbernat (the lacunar ligament); but such an action can injure the aberrant obturator artery ("the enemy below") and result in herniation or extensive blood loss.

The description of the origin, course, and relations of the common and external iliac vessels is clear and interesting in its manner of presentation. Bogros observes that one can draw a line beginning a centimeter or so below the navel in the midline to the midpoint of the inguinal ligament, thereby defining the underlying position of the iliac artery and its availability for palpation. He also observes that the femoral nerve emerges from the trough between the psoas and iliacus lateral to the external iliac artery some distance cranial to the inguinal ligament. This is an important consideration at the present time because of the frequent practice of placement of staples lateral to the internal inguinal ring in laparoscopic herniorrhaphy.

Some explanations of the fascial arrangements as presented by Bogros, particularly those concerned with the inguinofemoral region, would be unacceptable by many present workers. Among other things, he perceived that the fascia lata of the thigh provides the origin for the fascia lining the abdominal cavity and covering the walls of the abdomen externally, a concept which seems comparable to saying that the hand and fingers are extensions of, and derivatives of the thumb.

Of course, the primary objective of the thesis is that of elaborating a safe and well-defined course of approach for the surgical exposure of the inferior epigastric and external iliac arteries without injury to them and without invasion of the peritoneal

cavity. His lucid description of the approach and its rationale is most enjoyable reading, and striking, especially for the time at which he wrote.

Three paragraphs in the thesis of Bogros give particulars of a space that has been wisely named the "space of Bogros," and perhaps to honor him for his excellent anatomic work. The descriptive information implicitly supports the opinions of Hureau et al., Bendavid, and ourselves that Bogros adequately defined the space named for him which exists between the peritoneum and the transversalis fascia. First, Bogros states, "The peritoneum, as it reflects from the iliac region of the anterior abdominal wall to the iliac fossa leaves in front a space 12-14 mm wide, where the external iliac artery ends and where the inferior epigastric artery begins." Second, "The external iliac artery and the first portion of the epigastric artery course along the iliac area of the abdominal wall. These vessels are so placed that they are only separated from the lower abdominal cavity by the peritoneum and a more or less thick cellular layer." Third, Bogros' thesis notes, "A loose layer of cellular tissue separates it (the inferior epigastric artery) from the transversalis fascia anteriorly. Posteriorly, a thicker layer of the same tissue separates it from the peritoneum, shortly beyond its origin."

Hesselbach's Triangle

Hesselbach's triangle (Fig. 1-10) is defined as having the inferior (deep) epigastric vessels as its superior or lateral border, the lateral edge of the rectus abdominis muscle as its medial border, and the inguinal ligament as its inferolateral border.

Fig(1-10)Hesselbach triangle as originally described (left) and as accepted today (right). Note that part of supravesical fossa lies within triangle. (Modified from Skandalakis PN, Skandalakis LJ, Gray SW,

Skandalakis JE. Supravesical hernia. In Nyhus LM, Condon RE (eds). Hernia (4th ed). Philadelphia: JB Lippincott, 1995, pp. 400-411; with permission.)

Most direct inguinal hernias and external supravesical inguinal hernias occur in this area. The rectus sheath, however, is the only suitable naturally-occurring structure for hernia repair. Of course, the epigastric vessels above the triangle cannot be used. The iliopubic tract or the pectineal ligament can be used rather than the inguinal ligament.

Presently, tension-free mesh prostheses are being more and more widely used in repairs of hernias of the abdominal wall. The prostheses provide dependable, relatively inexpensive and lasting support for the defective region.

Fossae of the Lower Anterior Abdominal Wall

The posterior surface of the anterior abdominal wall above the inguinal ligament is divided into three shallow fossae (Fig. 1-11). Located on either side of the midline, these fossae are marked by the obliterated embryonic urachus, extending from the dome of the bladder to the umbilicus (median umbilical ligament). Laterally, the fossae are separated by the medial umbilical ligaments (obliterated umbilical arteries) and the lateral umbilical ligaments (inferior or deep epigastric arteries).

Fig(1-11)Fossae of anterior abdominal wall and their relation to sites of groin hernias. A, Umbilicus. B, Median umbilical ligament (obliterated urachus). C, Medial umbilical ligament (obliterated umbilical

arteries). D, Lateral umbilical ligament containing inferior (deep) epigastric arteries. E, Falciform ligament. Sites of possible hernias: 1, Lateral fossa (indirect inguinal hernia); 2, Medial fossa (direct inguinal hernia); 3, Supravesical fossa (supravesical hernia); 4, Femoral ring (femoral hernia). (From

Rowe JS Jr, Skandalakis JE, Gray SW. Multiple bilateral inguinal hernias. Am Surg 1973;39:269-270; with permission.)

The fossae are as follows:

The lateral inguinal fossae (Fig. 1-11), lateral to the inferior epigastric arteries, contain the internal inguinal rings. They are the site of indirect inguinal hernias.

The medial inguinal fossae, between the inferior epigastric arteries and the medial umbilical ligaments, are the site of direct inguinal hernias.

The supravesical fossae, between the medial and median umbilical ligaments, are the site of external supravesical hernias.

The supravesical fossa partially overlies Hesselbach's triangle, so that the medial umbilical ligament lies within it. Therefore, a hernia through either the medial or the supravesical fossa is a direct inguinal hernia. Depending upon location, a direct hernia may be inguinal (in the medial fossa) or supravesical (in the supravesical fossa).

The termination of the aponeurosis of the internal oblique muscle and the transversus abdominis muscle meet to form the "conjoined tendon" in only a very small percentage of subjects, if in any. Because the presence of this entity is very rare, we prefer the lateral border of the rectus sheath as the landmark for a supravesical hernia.51

Spaces between the Inguinal Ligament and the Iliopectineal Line

Between the inguinal ligament and the superior pubic ramus is a space organized into three compartments: neuromuscular, vascular, and femoral canal (see Fig. 1-6). The most lateral of these is the neuromuscular. This area contains the iliopsoas muscle, the femoral nerve, and the lateral femoral cutaneous nerve.

Medial to the area containing the iliopsoas muscle, the femoral nerve, and the lateral femoral cutaneous nerve is the vascular compartment which contains the femoral artery and vein.

Bony Elements Related to the Inguinal Area

Those parts of the pelvis and the pelvic brim related to the soft parts of the inguinofemoral area are:

Iliopectineal line

Pubic tubercle

Symphysis pubis

The iliopectineal line and the arcuate line form the terminal line (linea terminalis) of the pelvis. The iliopectineal line of the pubic bone and the pubic crest creates the

Fig(1-12)Some bony elements and ligamental parts of inguinal femoral area. ASIS, Anterior superior iliac spine. PT, Pubic tubercle. (Modified from Skandalakis JE, Colborn GL, Gray SW, Skandalakis LJ,

Pemberton LB. The surgical anatomy of the inguinal area — Part 1. Contemp Surg 1991;38:20-34; with permission.)

anterior part; the arcuate line of the ileum makes up the posterior part. The terminal line extends from the promontory of the sacrum to the pubic symphysis (Fig. 9-44).

The iliopectineal line is of greater concern than the arcuate line in the anatomy of hernias for the following reasons:

Tendinous fibers of the pectineus muscle are attached to the iliopectineal line in toto

The pectineal ligament of Cooper is attached to the medial part of the iliopectineal line

The iliopubic tract inserts upon it.

At the medial end of the iliopectineal line lies the pubic tubercle. The medial portions of the lacunar ligament and the "conjoined tendon," when present, attach to the pubic tubercle.

Blood Supply of the Inguinal Area

Arteries

The blood supply to the inguinal area is very rich. We do not attempt to fully describe it here, but rather to present only some aspects of it. For descriptive purposes, it may be divided into a superficial part for the subcutaneous fat and a deeper part for the musculoaponeurotic components.

Three superficial branches of the femoral artery help supply the abdominal wall below the umbilicus, giving off rami that pass upward in the subcutaneous connective tissue. From lateral to medial they are:

Superficial circumflex iliac artery (close to the iliac crest)

Superficial epigastric artery (at the midgroin area, with an upward vertical orientation)

Superficial external pudendal artery (inferior to the inguinal ligament at the fossa ovalis)

The superficial epigastric artery anastomoses with the contralateral artery, and all have anastomoses with the deep arteries.

Deep arteries lie between the internal oblique and transversus abdominis muscles. They are:

10th and 11th posterior intercostal arteries

Anterior branch of the subcostal artery

Anterior branches of the four lumbar arteries

Ascending branch of the deep circumflex iliac artery

The blood supply to the rectus sheath is from the superior and inferior epigastric arteries, which frequently anastomose. The inferior epigastric artery enters the rectus sheath at or about the semicircular line of Douglas (arcuate line), between the rectus muscle and the posterior lamina of the sheath. The deep arterial network of the abdominal wall is composed of the inferior epigastric artery and the deep circumflex iliac artery. Both originate from the distal part of the external iliac artery.

The inferior epigastric artery gives off two branches:

External spermatic (cremasteric), which becomes part of the spermatic cord

Pubic, which crosses the ligament of Cooper and anastomoses with the obturator artery to occasionally become the aberrant obturator artery

The deep circumflex iliac artery is located outside the preperitoneal space, deep to the iliopsoas fascia, close to the iliopectineal arch. From its origin, the deep circumflex iliac artery passes laterally, at first deep to the fascia iliaca and then beneath the iliopubic tract. Its ascending branch passes upward vertically, just medial to the anterior superior iliac spine and between the transversus and internal oblique muscles. In laparoscopic herniorrhaphy, the deep circumflex iliac artery is subject to injury by staples or suture placement in anchoring mesh prostheses, and results occasionally in the formation of a hematoma.

Veins

The veins follow the arteries. The inferior epigastric veins and the deep circumflex iliac veins, two for each artery, empty into the external iliac vein. Beware: remember the venous circle of Bendavid88 referred to previously in the presentation on the space of Bogros.

Lymphatics of the Inguinal Area

Inguinal lymph nodes may be divided into:

Superficial nodes between the superficial fascia and the fascia lata

Deep inguinal nodes beneath the fascia lata

Aberrant inguinal nodes within the inguinal canal

Superficial Inguinal Nodes

Superficial inguinal nodes have been divided for more than 100 years into five arbitrary zones.96,98 These zones, centered on the termination of the great saphenous veinIn 450 dissections, Daseler et al.98 reported that the number of lymph nodes varied from 0-8 in zone 1, from 0-7 in zone 2, from 0-3 in zone 3, from 0-9 in zone 4, and from 0-3 in zone 5.

Although the number of nodes is small (Daseler and colleagues98 found an average of only 8.25 nodes per leg dissected), these nodes are perhaps the largest single group of lymph nodes in the body. The number of nodes varies from 4 to 25, and is inversely proportional to the size of the individual nodes.

Within the zones, the nodes lie along the blood vessels (see Fig. 1-13). The superolateral nodes (zone 1) extend along the superficial circumflex iliac vessels inferior to the inguinal ligament. Haagensen and associates96 found a few above the ligament on the aponeurosis of the external oblique muscle. The superomedial nodes (zone 2) are associated with the superficial epigastric and the external pudendal vessels as far as 1 cm above the inguinal ligament.

Fig(1-13)Lymph node distribution around great saphenous vein and its tributaries. (Modified from Skandalakis JE, Gray SW, Rowe JS Jr. Anatomical Complications in General Surgery. New York:

McGraw-Hill, 1983; with permission.)

Inframedial nodes (zone 3) were absent in 20 percent of dissected anatomic specimens examined by Daseler and colleagues;98 in 37 percent, only a single node was present. In the inferolateral quarter (zone 4), a chain of nodes lies lateral to the great saphenous vein. A node at the junction of the great and accessory saphenous veins is relatively constant. The central zone (zone 5) had no nodes in 84 percent of dissected anatomic specimens, and only a single node in another 15 percent.

Deep Inguinal Nodes

Two or three small nodes lie beneath the fascia lata along the femoral vein. The largest (the node of Cloquet), at the femoral ring between the vein and the lacunar ligament, is almost always present. Metastasis to Cloquet's node, like metastasis to apical nodes of the axilla, makes the prognosis poor. All of these nodes lie within the boundaries of the area of radical excision.

Aberrant Nodes

Aberrant nodes include some small nodes in the inguinal canal, over the symphysis pubis, and at the base of the penis.

Pathways of Lymph

The superficial inguinal nodes receive lymph from the entire lower limb, the infraumbilical abdominal wall, buttock, perineum, anal canal, penis, and the scrotum

or the labia and the vagina external to the hymen. Drainage from the glans penis or glans clitoridis is usually said to be to the deep inguinal nodes.

Nerve Supply of the Inguinal Area

The ilioinguinal and genitofemoral nerves are prone to injury in laparoscopic procedures (Fig. 1-15).

After leaving the superficial inguinal ring, the ilioinguinal nerve subdivides into: 1) large anterior scrotal or labial branches; 2) a small pubic branch to the lower pubic area and the base of the penis or clitoris; and 3) crural branches to the upper inner thigh and inguinal crease.100

The ilioinguinal nerve was present in 97.5 per cent of 200 bodies studied by Zaluska.101 It originated from the lumbar plexus independently in 72.5 per cent, was combined together with the iliohypogastric in 25 per cent, and was absent in 2.5 per cent. The ilioinguinal nerve was formed by one root (usually L1; rarely, L2) in 92.5 per cent and by two roots in 5 per cent. According to Bardeen,102 the ilioinguinal nerve is composed of fibers from L1 in 89.8 per cent, arising from L1 alone in 51.5 per cent and from T12 and L1 in 38.3 per cent. In 6.6 per cent, the ilioinguinal nerve was replaced by the genital branch of the genitofemoral nerve. Bardeen102 observed that the ilioinguinal and iliohypogastric were combined in about 15 per cent of cases.

According to most anatomy texts (e.g., Gray's Anatomy103), the ilioinguinal nerve passes within the abdominal wall, above the iliac crest, deep to the internal oblique to a point just medial to the anterior superior iliac spine, at which point it becomes visible between the external and internal obliques and then passes into the inguinal canal. In our investigation, the ilioinguinal nerve crossed the iliac fossa in 25.5 per cent of cases.

The genitofemoral nerve typically divides into a femoral (lumboinguinal) branch and a genital (external spermatic) branch. The femoral branch passes in the femoral sheath beneath the inguinal ligament, ventral or lateral to the femoral artery, and supplies the skin of the thigh in the vicinity of Scarpa's (femoral) triangle. We have observed that the femoral branch may communicate with, or be replaced by, an intermediate femoral cutaneous nerve arising in the iliac fossa. The genital branch exits the abdomen in the inferomedial angle of the deep ring, in company with the cremasteric branches of the inferior epigastric vessels. Lying deep to the cremaster, it supplies that muscle and some of the skin of the scrotum. The genital branch was frequently combined with the ilioinguinal nerve (7.7%) in the present study.

Within the deep inguinal ring the genital branch is deep medially, with the cremasteric vessels; i.e., medial in such a way that the suturing of the crura of the internal ring is above and superficial to the position of the nerve. Therefore, entrapment of the genital branch of the genitofemoral nerve at the deep ring should occur very rarely - perhaps just in those unusual cases in which the genital branch and the ilioinguinal nerves are combined and therefore located more superficially. Leaving the deep inguinal ring, the genital branch is located at the lower margin of the iliopubic tract, together with

the cremasteric vessels. Entrapment and injury of the nerve can take place only with deep suturing of the iliopubic tract (see Figs. 1-7).

The surgeon should also be careful not to injure the following three nerves: lateral femoral cutaneous, femoral, and anterior femoral cutaneous (a frequent variation).

Fig(1-15)Nerves of inguinal region. (Modified from Gray SW, Skandalakis JE. Atlas of Surgical Anatomy for General Surgeons. Baltimore: Williams & Wilkins, 1985; with permission.)

Summary of the Inguinofemoral Area

There can be little question that one of the greatest students of inguinal anatomy was Dr. Chester McVay. His collective review of the subject,61 as well as his other publications, made him the authority. Rather than paraphrase his dogma, we have chosen to reprint his summary of inguinal anatomy in his own words.

The three musculoaponeurotic laminae of the inguinal region are covered on each of their two flat surfaces by fascial sheets. The innermost of these six fascial plates is called the transversalis fascia and the outermost the innominate fascia; the four remaining fascial laminae have never been named.

The medial three-fourths of the inguinal ligament is a free edge when divested of its fasciae; it is not a strong cordlike structure and is only slightly thicker than the external oblique aponeurosis. It is anchored in position by fascia from which it can be readily displaced. The lacunar ligament is not a special triangular plaque between the inguinal ligament and the pubic pecten but merely part of the pubic insertion of mutually parallel external oblique aponeurotic fibers. It does not form the medial boundary of the femoral ring and cannot be seen from the abdominal side of the intact inguinal region. The external oblique aponeurosis, like the external oblique muscle, is covered on either surface by a sheet of fascia, the external one of which is the thickest and called the innominate fascia by Gallaudet. The intercrural fibers usually lie within the substance of the fascial plane on the external aspect of the external oblique aponeurosis, but in a few instances, some of these fibers pass between the aponeurotic fibers and continue their course within the fascial plane on the internal aspect of the aponeurosis. The subcutaneous inguinal ring is a triangular defect with the base on the pubic crest and the apex directed superolaterally. None of the aponeurotic fibers contribute to the external spermatic fascia; the latter is composed entirely of the fasciae that invest the aponeurosis and fuse in the defect left by the diverging aponeurotic fibers. Intercrural fibers may be incorporated in the external spermatic fascia.

The inguinal portion of the internal oblique muscle, including the cremaster muscle, originates from the iliopsoas fascia deep to the inguinal ligament, not from the inguinal ligament; and the lowest fibers of the internal oblique muscle insert onto the pecten of the pubis. The muscle fibers of the cremaster muscle usually descend well grouped together on the posterolateral aspect of the cord and lose themselves on the testicle; rarely, a few muscle fibers can be found ascending on the medial aspect of the cord to a pubic insertion.

The inguinal portion of the transversus abdominis muscle originates from the iliopsoas fascia deep to the inguinal ligament in common with the corresponding portion of the internal oblique and not from the inguinal ligament. The pubic insertion of the lowermost portion of the transversus abdominis muscle is primarily onto that portion of the iliopectineal line known as the pecten. The transversus muscle and aponeurosis formed a complete inguinal stratum in 93 percent of the 362 inguinal regions studied. The fasciae on either surface of the transversus abdominis aponeurosis are carried out on the spermatic cord as the internal spermatic fascia and prolonged inferiorly on the femoral vessels as the anterior component of the femoral sheath. When muscle fibers from the transversus abdominis layer are carried down on

the cord, they lie within the confines of the internal spermatic fascia and do not contribute to the cremaster layer.

Beneath the linea semicircularis, the medial continuation of the transversalis fascia splits to invest the rectus muscle. Illustrations which show the fascia transversalis passing entirely posterior to the rectus muscle, inferior to the fold of Douglas, are not correct. In 1 percent of the specimens, that portion of the transversus aponeurosis inferior to the linea semicircularis does not contribute to the rectus sheath but inserts directly into the lateral aspect of the rectus muscle with an interdigitation of fibers.

The femoral sheath is a prolongation of the parietal abdominal fasciae into the thigh around the femoral vessels. It is a perfect tube, with the anterior component a direct continuation of the fascial investments of the transversus and internal oblique muscles, although principally composed of the transversalis fascia, and the posterior component is a slip from the iliopsoas fascia, not the iliopsoas fascia proper. Within the femoral sheath proper is a visceral sheath continuous with the preperitoneal connective tissue.

The medial boundary of the femoral ring is the lateral edge of the aponeurosis of insertion of the transversus abdominis muscle onto the pecten of the pubis, not the lacunar ligament.

The falx inguinalis is the lateral expansion of the rectus abdominis tendon of insertion onto the pecten of the pubis. The conjoined tendon does not exist after careful dissection, and its falciform margin is usually an artifact of dissection. The ligamentum interfoveolare is a thickening in the transversalis fascia at the medial side of the abdominal inguinal ring due to the reduplication of this fascial layer by the evaginated internal spermatic fascia.

In repair of a direct inguinal hernia, the aponeurosis of the transversus and internal oblique muscles should be sutured to the fibrous ridge covering the pecten of the pubis, Cooper's ligament, superior pubic ligament, as far laterally as the femoral vein and not to the inguinal ligament. This will give a firm, nonyielding repair and, in addition, obviate the occurrence of a femoral hernia. Aponeurosis, not fascia, should be the principal constituent in the repair of any hernia.

Our respected friend Réné Stoppa and his colleagues have recently presented new information about inguinofemoral anatomy. We present two excerpts verbatim from their works, with accompanying illustrations.

The authors have intraoperatively observed that the retroparietal components of the spermatic cord are contained within a spermatic sheath, the patency and morphology of which have been established. Anatomical dissections have identified its relations with the inter-parieto-peritoneal fibrous structures and the external iliac vessels. Careful preservation of this "spermatic sheath" during the mobilization of the cord is recommended to avoid pervascular sclerosis due to contact with the large mesh prostheses used in groin hernia repairs. This is important to preserve as much sheath as possible and may be potentially useful if a reoperation is required for vascular surgery, organ transplant, or lymph node dissection (Figs. 9-49, 9-50, 9-51).106

Histology of the Inguinofemoral Area

Waugh and Read108 in 1972 were the first, or among the first, to study the relationship of collagen synthesis and inguinal hernia. In two later reports, Peacock109,110 discussed the local surgical biology of patients with hernia, emphasizing metabolic connective tissue abnormalities. He stated that hernia is the result of an imbalance between normal collagen synthesis and normal collagen degradation.

Berliner111 performed biopsies from the transversalis fascia close to the internal ring at the site of direct hernias and from normal transversus abdominis aponeurosis superior to the bulge of a direct hernia. He concluded that wound healing requires a fibroblastic response and an adequate supply of oxygen to initiate an ongoing balance of collagen synthesis and enzymatic lysis. An incision into the posterior wall of the inguinal canal that is closed and without tension is necessary to stimulate fibroplasia where it will be useful. Sutures under tension stimulate an inadequate fibroblast response.

Laparoscopic Anatomy of the Inguinal Area

The laparoscopic anatomy of the inguinal area from the peritoneum to the posterior surface of the myopectineal orifice of Fruchaud was detailed by Brick and colleagues.115 Their findings of laparoscopic and open dissection of several cadavers are excerpted below (Figs. 9-57, 9-58).

In the majority of our laparoscopic dissections, we found it necessary to use the transperitoneal approach, at least initially, because the peritoneum and transversalis fascia were frequently fused posterior to the rectus and were inseparable, even with the Hassan cannula or balloon inflation. This fusion of tissue is attributable in part to the advanced age (average 74 years) and associated previous operations in such a population pool. Except when the cadaver possessed much extraperitoneal fat, it was usually very easy to see the color and arrangement of fibers to guide us to the identification of the transversus abdominis muscular arch and the iliopubic tract. Preperitoneal fatty tissue and membranous tissue can be reflected or removed from these entities to expose the internal ring, gonadal vessels (male), and ductus deferens or round ligament.

In reflecting the peritoneum from the inguinal triangle, we have seen some specimens in which the medial umbilical fold was near to, or even overlaid the lateral umbilical fold, making it somewhat more difficult to identify and clearly expose the inferior epigastric vessels. In such cases, the lateral surface of the bladder was often nearer the internal inguinal ring than expected. This problem was worse in specimens with much extraperitoneal fat, in which cases the bladder could not be seen immediately. In some bodies the bladder was quite dilated, extending a considerable distance above the pubis, even though empty. It should be remembered that the lateral edge of the bladder can lie just medial to the medial umbilical ligament, near which point the

patent part of the umbilical artery supplies superior vesical branches to the bladder. If the medial umbilical ligament appears to be more lateral than anticipated, one should guard against an unexpected encounter with, and injury to, the urinary bladder.

In most cases, it is possible to identify and protect the genital branch of the genitofemoral nerve because it lies upon, and runs parallel with, the external iliac artery; it is often seen rather early, following the reflection of the peritoneum and fatty tissue away from the external iliac and testicular vessels. In one case, wherein the genital branch of the genitofemoral appeared to be more than 2 mm in diameter, it proved to be a combined ilioinguinal and genital branch which, after traversing the spermatic cord, exited the inguinal canal at the external inguinal ring, thereafter following the normal course of distribution of the ilioinguinal nerve.

In every specimen we have dissected thus far, one or more additional nerves of varying size were found superficial to, or between, the fascial laminae over the iliacus muscle, between the femoral branch of genitofemoral and the usual position of the lateral femoral cutaneous nerve, just medial to the anterior superior iliac spine (Fig. 9-59). These are described briefly here to emphasize the unpredictability of the nerves which pass through the region.

According to texts and atlases of anatomy or surgery, the only nerve typically described just lateral to the internal inguinal ring is the femoral branch of the genitofemoral nerve. The exposed nerve was in several cases larger than that anticipated for the femoral branch of genitofemoral nerve, which is usually a relatively small cutaneous nerve that supplies only the skin over the region of the femoral triangle of the thigh. When the nerve was dissected out in two cadavers, it proved to be an anterior femoral cutaneous nerve. In four cadavers, the nerve was a combination of the femoral branch of genitofemoral and the lateral femoral cutaneous nerve. In these instances, at the point where the lateral femoral cutaneous nerve began passage beneath the iliopubic tract, the nerve was at least two centimeters medial to the anterior superior iliac spine.

Frequently a small or medium sized, unnamed nerve (0.5-2.5 mm) was seen piercing the tract one centimeter or more lateral to the internal inguinal ring, thereafter providing twigs to the lower part of the anterior abdominal wall musculature; in other specimens, however, nerves seen in this position provided cutaneous supply to the anterior aspect of the thigh; in two cases, the nerve proved to be the source of an aberrant ilioinguinal nerve or lateral femoral cutaneous nerve. In two cases, a nerve which was seen initially lying deep to the position of the femoral branch of the genitofemoral nerve proved to be an early rising nerve to the pectineus muscle of the thigh. With two types of exceptions, the nerves identified lateral to the external iliac artery passed through the iliopubic tract, lateral to the internal inguinal ring. The exceptions were the normal and the aberrant lateral femoral cutaneous nerve and the early rising motor nerve to the pectineus.

Just lateral to the external iliac artery, halfway between the anterior superior iliac spine and the pubic tubercle, the femoral nerve lies in the groove between the psoas major and the iliacus (Fig. 9-59). It is not seen unless the iliacus fascia covering is removed, even though it appears from beneath the psoas major approximately 6 cm superior (craniad) to the iliopubic tract. The femoral nerve, like the lateral femoral

cutaneous nerve, leaves the abdomen by passing deep to the deep circumflex iliac vessels, the iliopubic tract, and the inguinal ligament. An early rising anterior femoral cutaneous nerve lies ventral to the femoral nerve; it can course either through, or deep to, the iliopubic tract. In two cases, we have seen the nerve to the pectineus lying just superficial to the femoral nerve. After passing beneath the inguinal ligament, this nerve coursed deep to the femoral vessels to reach the pectineus muscle.

The deep circumflex iliac artery and vein leave the lateral aspect of the external iliac vessels just deep to, or slightly cranial to, the inferior edge of the iliopubic tract (Fig. 9-59). In some cases, therefore, the deep circumflex iliac vessels lie deep to the inferior (posterior) one-third of the iliopubic tract. These vessels take origin from the external iliacs at the same level, or up to several centimeters distal to the origin of the inferior epigastric artery and vein. Because the inferior epigastrics initially curve sharply inferiorly from their origin, before ascending the anterior abdominal wall, it is easy not to note how proximally they arise, in comparison with the deep circumflex iliac vessels.

Medial to the inferior epigastric vessels, one can usually identify without difficulty the pectineal ligament and then the medial border of the femoral ring (Fig. 9-59). As the fatty and membranous connective tissue are cleared from this area, we always encountered iliopubic veins of varying caliber, and in half the bodies, we noted the presence of an aberrant obturator artery that crossed the femoral ring before crossing the pectineal ligament. The aberrant obturator artery typically provides one or more branches to the tissues within the femoral canal. The presence of such vessels, both normal and aberrant, was usually not suspected, for it takes little connective tissue to conceal them from sight. In one case, we found a large suprapubic tributary to the external iliac vein only after we saw the large, gaping opening where the tributary had ended before it was avulsed.

Large external iliac lymph nodes may conceal the presence of nerves just lateral to the external iliac vessels. Lymph vessels and nodes medial to the external iliac vein can disguise the presence of suprapubic or aberrant obturator vessels. These lymphatic elements are continuous with those within the femoral canal and, at the abdominal opening of the canal, often totally obscure an aberrant obturator artery, aberrant obturator vein, or both, of rather large diameter.

Topography

The topographic laparoscopic anatomy of the inguinal area (surgical layers, spaces, fossae, and the other anatomic entities between) is listed below.

Layers

The order of the surgical layers:

1. Peritoneum

2. Posterior lamina of the transversalis fascia

3. Anterior lamina of the transversalis fascia and the transversus abdominis aponeurosis

Spaces

The order of the surgical spaces:

1. Space of Bogros (space between the peritoneum and the posterior lamina of transversalis fascia)

2. Vascular space (space between the posterior and anterior laminae of the transversalis fascia). This includes the aponeurosis of the transversus abdominis muscle.

Fossae

The order of the fossae, from midline to periphery:

1. Supravesical

2. Medial

3. Lateral

Each of these fossae is the potential home of a hernia.

The myopectineal orifice of Fruchaud is present at the fusion of the anterior lamina of the transversalis fascia with the transversus abdominis aponeurosis. It is the potential site for one or a combination of inguinofemoral herniations.

O'Malley et al.116 studied the anatomy of the peritoneal aspect of the deep inguinal ring from a laparoscopic standpoint (Figs. 9-60, 9-61). They summarized their findings as follows:

There are a number of important structures to be avoided in suturing or stapling during laparoscopic inguinal herniorrhaphy, not all of which are easily identifiable at laparoscopy. This is particularly so of the ductus deferens. Measurements were taken of the angle made by the ductus deferens with testicular vessels, and of the thickness of tissue in the vicinity of the internal ring into which sutures or staples are likely to be inserted. The angle (mean ± SD) made by the ductus with testicular vessels was 38.6 ± 4.4° on the right, and 48.6 ± 7.2° on the left (P <0.05) (measurements for right and left sides taken from different cadavers). Thickness of tissue around the ring (peritoneum, transversalis fascia and intervening connective tissue) varies at different sites, being greatest lateral to the testicular vessels (2.2 ± 0.4 mm) and least over the ductus (0.2 ± 0.1 mm). The angle measured constitutes the apex of the "triangle of doom,"117 and with its use the position of the ductus deferens may be predicted and the underlying external iliac vessels avoided when stapling during herniorrhaphy.

Summary of Laparoscopic Anatomy

A study of the laparoscopic cadaveric anatomy of the inguinal area by Skandalakis et al.118 is excerpted here.

Figures 9-37, 9-62, and 9-63 will be the basis of orientation for the study of anatomic entities, folds, and spaces with which the laparoscopist should be familiar.

In the peritoneum, three fossae are formed. They are separated by folds or ligaments; these are formed by anatomic entities that elevate the peritoneum. The fossae from the midline to the periphery are the:

Supravesical fossa (A in Fig. 9-64), between the median umbilical ligament or fold (the urachus, obliterated or not) and the medial umbilical ligament or fold (the obliterated segment of the umbilical artery). This is the home of the external supravesical hernia.

Medial fossa ( B in Fig. 9-64), between the medial umbilical ligament or fold and the lateral umbilical ligament or fold (inferior or deep epigastric artery and vein). This is the area in which the direct hernia is developed.

Lateral fossa (C in Fig. 9-64), lateral to the lateral umbilical ligament. Within the fossa is the deep inguinal ring, through which the indirect hernia develops. In many cases, with the peritoneum in place, the laparoscopist also will observe two underlying anatomic entities in the male: the gonadal vessels (bluish cordlike structures) and the ductus deferens (like a silver cord).

Under the peritoneum and between the peritoneum and the posterior lamina of the transversalis fascia is the space of Bogros, which is filled with variable quantities of preperitoneal fat. This is the area in which the laparoscopist will insert the prosthesis (see Fig. 9-37).

Another space is the area formed between the anterior and posterior laminae of the transversalis fascia; the inferior epigastric vessels are located within this area. Occasionally, the posterior lamina is very thin and unrecognizable. Then the space of Bogros extends to the anterior lamina of the transversalis fascia, which is the well-known "transversalis fascia." Within the lower part of the space of Bogros is the inguinal venous circle, which has been described recently by Bendavid88 and which forms a venous network for several tributaries (see Figs. 9-35, 9-37, 9-38, 9-39).

Remember

With gas insufflation into the inguinal area, the veins collapse. The laparoscopist should, therefore, be very gentle.

After the removal of fibrofatty tissues, the laparoscopist will see the most superficial anatomic entity, the inferior epigastric vessels. With further cleaning, the transversus

abdominis muscular arch and the iliopubic tract will be seen. Both are closely related to the internal ring: the arch forms the superior boundary, and the iliopubic tract forms the inferior boundary of the ring (Fig. 9-65). Neither the inguinal ligament (Poupart's) nor the lacunar ligament (Gimbernat's) can be seen from a laparoscopic standpoint. Cooper's ligament, however, will be seen at the pubic brim as a shiny white cordlike formation.

The external iliac artery and vein are located in a deeper plane within the triangle formed by the spermatic vessels and the ductus deferens. Distally, at the internal ring, these vessels lie to the right and left of the apex of the triangle, but, proximally in our dissections they were always within it. The origins of the inferior epigastric and deep circumflex iliac vessels are also within this area.

Another important triangle is the myopectineal orifice of Fruchaud (see Fig. 9-23B). Its boundaries are as follows.

Superior: Arch of the internal oblique muscle and the transversus abdominis muscle

Lateral: Iliopsoas muscle

Medial: Lateral edge of rectus abdominis muscle

Inferior: Pubic pecten

The iliopubic tract divides Fruchaud's orifice into two visible parts.

Above: the spermatic cord

Below: the external iliac vessels, covered by the anterior lamina of the femoral sheath (Figs. 9-66, 9-67).

The most lateral nerve is the lateral femoral cutaneous nerve. In most cases, it leaves the iliac fossa just medial to the anterior superior iliac spine. Superficial to the external iliac artery is the genital branch of the genitofemoral nerve. Lateral to the external iliac artery is the femoral branch of the genitofemoral nerve. Further, but not far enough away to avoid injury, is the femoral nerve (see Fig. 9-59), which lies in the trough between the psoas and iliacus muscles.

Several important vessels are medial to the deep inguinal ring:

Venous circle (venous network of the deep inferior epigastric vein, the iliopubic vein, the rectusial vein, the retropubic vein, and the communicating rectusioepigastric vein)88

Inferior epigastric artery and vein

Internal and external iliac artery and vein

Rectus vessels

Suprapubic and retropubic vessels

Aberrant obturator artery and/or vein (present in 30-40% of cases)

Remember the nerves lateral to the deep ring:

Lateral femoral cutaneous nerve

Genital branch of the genitofemoral nerve

Femoral branch of the genitofemoral nerve

Femoral nerve

Remember the vessels medial to and below the deep ring:

Venous circle

Inferior epigastric artery and vein

Internal and external iliac artery and vein

Muscular (rectus) vessels

Suprapubic vessels

Retropubic vessels

Aberrant obturator artery and/or vein (in 30-40% of cases)

Three danger areas are the Triangle of Doom,117 the Triangle of Pain,119 and the Circle of Death. (The originator of the term Circle of Death is unknown to the authors, and therefore, not cited.) A discussion of these three danger areas follows.

The Triangle of Doom (Fig. 9-70) is formed by the gonadal vessels laterally and the ductus deferens medially. These anatomic entities meet at the deep inguinal ring. Within this triangle are: external iliac vessels, deep circumflex iliac vein, genital branch of the genitofemoral nerve, and the femoral nerve (deep).

The Triangle of Pain (Fig. 9-71) is formed by the iliopubic tract inferolaterally and the gonadal vessels superomedially. The contents of this imaginary triangle include several nerves, such as lateral femoral cutaneous, anterior femoral cutaneous, femoral branch of genitofemoral, and femoral nerve.

The arterial network of the Circle of Death (Fig. 9-72) is formed by the common iliac artery, internal and external iliac arteries, obturator artery, aberrant obturator artery, and inferior epigastric artery. The venous counterparts are similar in name, course, and position.

Fig(1-16)Triangle of Doom. (Modified from Colborn GL, Skandalakis JE. Laparoscopic cadaveric anatomy of the inguinal area. Probl Gen Surg 1995; 12:13-20; with permission.)

Fig(1-17)Triangle of Pain. (Modified from Colborn GL, Skandalakis JE. Laparoscopic cadaveric anatomy of the inguinal area. Probl Gen Surg 1995;12:13-20; with permission.)

Fig(1-18)Circle of Death. (Modified from Colborn GL, Skandalakis JE. Laparoscopic cadaveric anatomy of the inguinal area. Probl Gen Surg 1995; 12:13-20; with permission.)

To avoid anatomic complications to the nerves, remember that most of the nerves are located lateral to the deep inguinal ring. Avoid stapling or suturing laterally below the level of the ring.

The lateral femoral cutaneous nerve is located lateral and deep to the iliopubic tract. The femoral branch of the genitofemoral nerve is lateral to and parallel with the external iliac artery. To avoid injury to the femoral nerve, do not dissect the iliacus fascia lateral to the spermatic vessels and external iliac artery.

Fig(1-19)Vessels and nerves related to iliopubic tract (highly diagrammatic). (Modified from Colborn GL, Skandalakis JE. Laparoscopic cadaveric anatomy of the inguinal area. Probl Gen Surg 1995;12:13-

20; with permission.)

To avoid complication to the vessels, use the inferior epigastric vessels to guide you to the great vessels, which are located below and medial to the deep ring. Carefully avoid the great vessels, since injury could cause fatal bleeding. To avoid ischemic orchitis, be sure not to injure the gonadal vessels, which travel toward the deep inguinal ring. The deep circumflex vessels are located parallel, but deep, to the iliopubic tract.

To avoid complications to the organs, you can protect the urinary bladder by identifying it. To locate it, find and follow the medial umbilical ligament. Avoid dissection medial to the ligament. Avoid injury to the ductus deferens in its course toward the internal ring. This is of utmost importance in bilateral herniorrhaphy repair, because sterility can result.

Remember

In approximately 30% of cases, the laparoscopic anatomy of one side will not be a mirror image of the other side.