Clinical anatomy of the inguinal
canal
A.
Anatomical
description
The inguinal canal runs ventromediocaudally through the anterior abdominal wall just above the inguinal ligament. Its length is about 4 – 6 cm. During the prenatal development of the male fetuses the vaginal process of peritoneum and the testis with its blood vessels pass through it into the scrotum, in the female fetuses it is the way for the descensus of the peripheral part of the round ligament of uterus into the labia majora.
Normal contents of the inguinal canal (postnatally)
Anatomical borders of the inguinal canal:
Clinical importance of the inguinal canal:
- during the fetal period it serves as a natural pathway for the descensus of some organs and structures – see above;
- in pathological situations some fasciae, peritoneum and intraabdominal organs are passing the canal as „inguinal herniae“ – similar pathological structures can develop also below the inguinal ligament through the vascular space (lacuna vasorum) – then we speak about „femoral herniae“.
Basic classification of the inguinal (groin) herniae:
Femoral herniae
pass the vascular space (lacuna vasorum), after the disruption of the femoral septum, mostly medially to the femoral vein; they protrude into subcutaneous layer in the same region as the inguinal herniae, e.g. anteromedially bellow the inguinal cutaneous sulcus.
Terminology of the anatomical
structures of the inguinal region
Latin terminology English
terminology
1 – m. obliquus externus abdominis 1 – external obl. abdominis muscle
2 – spina iliaca anterior superior 2 – sup. ant. iliac spine
3 – n. cutaneus femoris lat. 3 – lateral cutaneous femoral nerve
4 – ligamentum inguinale 4 – inguinal ligament
5 – m. iliopsoas 5 – iliopsoas muscle
6 – n. femoralis 6 – femoral nerve
7 – tractus iliopectineus 7 – iliopectineal tract
8 – a. femoralis 8 – femoral artery
9 – v. femoralis 9 – femoral vein
10 – nodi lymphatici ing. prof. 10 – deep inguinal lymphatic nodes
11 – for. obturatum 11 – obturator foramen
12 - ligamentum lacunare (Gimbernati) 12 – lacunar ligament
13 – adminiculum lineae albae 13 – adminiculum of linea alba
14 – ligamentum reflexum (Colesi) 14 – reflex ligament
15 – crus mediale 15 – medial crus
16 – crus laterale 16 – lateral crus
17 – fibrae intercrurales 17 – intercrural fibres
18 – linea alba 18 – linea alba
19 – umbilicus 19 – navel (umbilicus)
20 – m. obliquus internus abdominis 20 – internal oblique abdominis muscle
21 – m. transversus abdominis 21 – transversus abdominis muscle
22 – linea arcuata (Douglasi) 22 – arcuate line
23 – linea semilunaris (Spigeli) 23 – semilunar line
24 – m. rectus abdominis 24 – rectus abdominis muscle
25 – vasa epigastrica inferiora 25 – inferior epigastric vessels
26 – lig. interfoveolare 26 – interfoveolar ligament
27 – tendo conjunctivus 27 – conjoined tendon
28 – m. pyramidalis 28 – pyramidalis muscle
29 – anulus femoralis et septum femorale 29 – femoral ring and femoral septum
Other important structures to be learned:
1 – anulus inguinalis superficialis 1 – superficial inguinal ring
2 – anulus inguinalis profundus 2 – deep inguinal ring
3 – fossa (fovea) inguinalis medialis 3 – medial inguinal fossa (fovea)
4 – fossa (fovea) inguinalis lateralis 4 – lateral inguinal fossa (fovea)
5 – trigonum inguinale (Hesselbachi) 5 – inguinal (Hesselbach´s) trigonum
6 – lacuna vasorum 6 – vascular foramen
7 – lacuna musculorum 7 - muscular foramen
8 – chorda a. umbilicalis 8 – chorda of umbilical artery
9 – hernia inguinalis indirecta 9 – indirect (oblique) inguinal hernia
10 – hernia inguinalis directa 10 – direct inguinal hernia
11 – hernia inguinalis supravesicalis 11 – supravesical inguinal hernia
12 – hernia femoralis 12 – femoral hernia
13 – tractus iliopubicus 13 – iliopubic tract
14 – fascia abdominis subcutanea (Scarpae) 14 – subcutaneous abdominal fascia
15 – fascia abdominis spf. 15 – superficial abdominal fascia
16 – fascia m. obl. ext. abd. propria 16 – fascia of ext. obl. abd. muscle proper
17 – fascia transversalis 17 – transversalis fascia
18 – peritoneum 18 - peritoneum
19 – falx inguinalis 19 – inguinal falx
Recommended literature:
Groin hernias
(Clinical comments to the anatomy of the inguinal canal)
Autumn 2005
Viktor Balogh
3rd year, 8th group
Contents:
Inguinal herniae are basically divided into two main categories, according to the relationship of the hernial sac and hernial ring (gate) into the indirect (oblique) and direct ones. Direct herniae originate with the disruption of the posterior face of the anterior abdominal wall in the groin region, indirect herniae begin to enter the deep inguinal ring and continue to pass the whole inguinal canal, together with all normal structures (nerves, spermatic cord etc.). Except of them, some special forms of herniae are described:
- congenital inguinal hernia of newborns. This form of hernia is always indirect. The hernial gate (origin) is the deep inguinal ring. The inferior epigastric vesselsare located medially to the neck of the hernial sac. The posterior wall of the inguinal canal is short and always stout. If the hernial sac is large enough, then it protrudes through the superficial inguinal ring into the subcutis of the groin region. Sometimes, when the hernial sac and the inguinal ring are very large, the top of the hernia can continue into the scrotum as the scrotal hernia.
- the inguinal hernia of small children is an indirect inguinal hernia, not apparent in the newborns. It appears and is clinically important mostly during the first school years. It is not evident that its origin could be inborn. Until the age of 12 – 15 years the inguinal herniae can not be of direct form.
- indirect (oblique) inguinal hernia of the adults is more frequent than the direct one, and represents 65 – 90% of all groin herniae. In males it is three times more frequent then in the females. It is mostly evident around the 50th year of life. The hernial sac lies inside of the spermatic cord, which is therefore enlarged.
- combined (saddle-like) inguinal hernia is not too rare, because it represents 10 – 25% of all inguinal herniae. It is the case of contemporary appearance of both indirect and direct inguinal hernia, where two hernial sacs are present in one region. The larger one is usually that of the indirect (oblique) hernia, but at the same time a lesser hernial sac of direct hernia protrudes ventrally between the epigastric vessels and the pubic tubercle. During the surgical procedure (earlier diagnosis is not possible) a deep impression between both hernial sacs is apparent, done by the epigastric vessels running along the medial margin of the enlarged deep inguinal ring (which is something as a saddle between both sacs).
- pantaloon-like hernia is more expressed form of the previous hernia, very rare, developed after long-term neglect.
- a direct inguinal hernia is never congenital. It appears in the adult age, where it represents 10 – 30% of all inguinal herniae and belongs to the biggest problems of the inguinal herniology. The most important point on its repair is the evaluation of the quality of all inguinal structures and their reconstruction. It has also the highest percentage of most common complications of the surgical treatment – recurrence. In the case of the direct inguinal hernia the starting point is a weakness of the transversal fascia in the middle of the Hesselbach´s triangle (e.g. between the inguinal falx, interfoveolar ligament and the iliopubic tract). The direct hernia never reaches the scrotum. The hernial gate is usually very large, with not well apparent margins. The remnants of the disrupted transversal fascia cover the surface of the hernial sac and their value for the reconstruction of the bottom of the inguinal region is mostly poor. By small direct inguinal hernia the epigastric vessels run craniolaterally to the hernial neck. To very frequent contents of the sac of direct inguinal hernia belongs the bladder. The exact differentiation between indirect and direct hernia enables mostly first the surgical procedure – the diagnosis is clear after the elevation of the spermatic cord (thin by the direct hernia) and after the evaluation of the relationship of the hernial sac to the epigastric vessels.
- interstitial hernia can be theoretically present also in the inguinal region, but its differentiation has no practical value. In most cases it is a starting situation, in which the small hernial sac protrudes cranially between the internal obl. abd. and transversus abd. muscles. The surgical solution of this form of hernia is standard (e.g. as in the cases of other inguinal herniae).
- Richter´s hernia is a rare case of incarceration (strangulation) of part of small intestine, sometime with necrosis of its wall by contemporary preservation of patency.
- Littré´s hernia is also rare. The content of the hernial sac is the Meckel´s diverticle (normally present at 2% of population).
- Imbert´s hernia is another rare case of right-side inguinal hernia, which appears some months or years after appendectomy. In that case the appendectomy was done by changing incision, during which the iliohypogastric and ilioinguinal nerves were cut. The result of this damage is the hernia.
The first historical sources come from Egypt, where the herniae were treated conservatively by percutaneous pressures with bandages. The very first description of the surgical treatment of hernia comes from the 1st century B.C. (Roman surgeon Celsus). The incision ran along the inguinal sulcus or scrotum, the hernial sac was excised and the procedure was usually finished by orchiectomy. His contemporary Heliodorus described as the first one the torsion of the hernial sac before its reflection. During the next nearly two thousands of years no substantial progres was evident, until the time of Joseph Lister. The exact pathological classification of herniae was provided during the second half of the 18th and first half of 19th century (Antonio Scarpa in Italy, Sir Astley Cooper in England). Hesselbach described exactly the inguinal canal short after Cooper. From the year 1846 (origin of the era of the general anesthesia) and after the principles of antiseptic procedures were postulated by J. Lister, the surgical techniques for the treatment of the inguinal herniae were improved substantially.
In year 1881, for the first time after the Roman time, Lucas Championiére opened the inguinal canal during the herniotomy. First translation of the spermatic cord and a real hernioplasty provided Edoardo Bassini from Padova, and was thus called „father of the modern surgery of the herniae“. But, nevertheless, this title belongs probably more to Marcy, born in Massachussetts and a pupil of Lister. He described as the first the closure of the deep hernial ring with the fenolised catgut. Marcy did this procedure in year 1869, published two years later – this is why he did it 15 years earlier than Bassini. But, finally, Bassini´s method was officially accepted and preferred in comparison with the Marcy´s technique.
Every surgeon makes a suture of the int. obl. abd. and transversus abd. muscles to the inguinal ligament behind the spermatic cord. But, no one makes the eversion of the aponeurosis of the ext. obl. abd. muscle. This procedure was introduced in USA by E.W. Andrews in 1895. Nevertheless, this procedure was called after Halsted. Halsted´s and Bassini´s techniques differ namely due to the fact that the first one lays the spermatic cord anteriorly to the aponeurosis of the ext. obl. abd. muscle, the second one behind it. Moreover, Halsted closes the redundant veins around and resects the bundles of the int. obl. abd. muscle, to reduce the size of the spermatic cord and to enable the lateral shift of the deep inguinal ring. Later on, Halsted described a technique by which he created a flap from the aponeurotic bundles of the ext. obl. abd. muscle, used for the final plastic procedure. But even he was not successful in discovering the importance of the incision of the inserting tendon of the rectus abdominis muscle.
A.H. Ferguson is responsible for the next progress in the reconstructive procedures by herniotomy. He left the transpositions of the spermatic cord and accented the necessity of the adaptation of the transversal fascia.
A. Cooper described as the first the ligament called after him in year 1804 – he thought it to be important for the surgery of the herniae. This proposal was worked out by Lotheisen 1898, who discovered a disturbed inguinal ligament by the recurrent hernia. Nevertheless, the hernioplasty using the Cooper´s ligament was not widely accepted in USA before 1948. At that time McVay published vast anatomical and physiological study on groin, together with his own proposal of the hernioplasty. He proclaimed that there is no reason for the suture of the transversal fascia to the inguinal ligament, until the fascia and the aponeurosis of the transv. abd. muscle normally insert into the Cooper´s ligament. There is no reason for the disturbing of that relationship.
From the first real hernioplasty done by Bassini more than 100 years ago, all next surgical methods and their modifications used a suture of the tissues under the tension.
In the routine practice, from the begining of the 20th century, three types of the surgical treatment of the inguinal herniae were used. The first was the Bassini´s method, used until now, and the soon left methods of Mac Even and Kocher. Until the mid of the eighties the procedures of the sutures under tension were used, now the tensionless procedures are more popular - this technique has a lesser amount of the postoperative complications, and not higher recurrence. Furthermore, this technique avoids the dissection of the groin nerves which minimalises the amount of the postoperative neuralgic complications. Also the use of the monofilmentous materials and local administration of antibiotics reduce the risk of the infection to the minimum.
As the last one was introduced into the menu of the hernioplastic procedures the extensively developing laparoscopic method. It was not accepted by the traditionalistic surgeons immediately /argueing for excellent results of the classical surgical access including the one-day-surgery results using the local anesthesia), but, in general, it has many advantages: minimal postoperative pain, substantial shortening of the postoperative care and faster return of the patient to the normal physical activities, lesser traumatisation of the tissues and the placement of the mesh preperitoneally – e.g. into the best place due to the way of the origin of the herniae. All procedures are done without tension, in comparison with the previous techniques.
Now, at the end of the century, they are basically three main surgical methods for the treatment of the inguinal herniae:
Ad 1.
Most of the patients in the Czech republic are treated by some of the classical methods. They are not only rational and economic reasons for that, but also some subjective ones, above all the traditions of the surgical departments and confidence in some methods. The use of the classical method is in our conditions fully indicated in cases of congenital and indirect herniae in adolescent patients. There is a general opinion that the classical method is appropriate for the treatment of both indirect and direct inguinal herniae of small and middle size in 40 – 50 – year old patients. The older the patients are the lesser is the indication of the classical method. Very controversial is the use of this method by treatment of recurrence of hernia. In most of the foreign publications (namely in the American ones) from the nineties is defined for the classical method as the golden standard the Shouldice´s procedure (e.g. the longitudinal incision of the transversal fascia and its suture with two lines of sutures). This method, although very popular in the literature since the half of eighties, have not found larger popularity in the Czech surgical community, even presenting minimal amount of postoperative complications and admirably low frequency of recurrencies. In our conditions, on the other hand, the use of classical methods after Marcy, Bassini, Mc Vay and Halsted is very popular, also for the treatment of complicated inguinal herniae. Great advantage of the classical methods is also the fact, that they can be used in any surgical department, without any demand on special material and instrumental equipment.
Ad 2.
Also the tension-free-method of Lichtenstein (with placing of the polypropylene mesh under the aponeurosis of the ext. obl. abdominis muscle or preperitoneally) was not substantially expanded in our conditions. Although it is technically relatively simple and usable in many cases. The published results are better then those by the classical procedures, especially by lesser amount of recurrences. The indications for the primary Lichtenstein´s method are both direct and indirect herniae, also large and recurrent ones. The natural contraindication is the infection in the groin region and in the genitofemoral sulcus, because the inflammatory post-operative complications are very unpleasant. The indications for the use of the mesh are more frequent in higher age and by large defects of the transversal fascia. By treatment of the hernial recurrence today the endoscopic procedure is preferred. Certain disadvantages of Lichtenstein ´s method are financial demands (higher price of the mesh) and theoretically higher risk of infections.
Ad 3.
Laparoscopic-endoscopic treatment of the inguinal hernia has large advantages by repair of hernial recurrences, by the treatment of bilateral herniae or in the combination of both inguinal and femoral hernia. The method is also profitable by groin and genitofemoral sulcus infections. In all other indications it can be an alternative to the other methods. To its advantages belong also a low amount of inflammatory complications and recurrences, low post-operative pain and soon return of the patients to their normal physical and working activities. To its certain disadvantages belong higher price of the procedure and the necessity of the special material and endoscopic equipments.
Closure:
The whole problematic dealing with indications, technical details of advantages and disadvantages of different methods is in fluent development. Except of some convincing and generally accepted indications, it is not possible today to offer an univocally valuable direction for hernial treatment, which could be presented as a surgical dogma. There is only one law valid, as in the rest of the surgery: the only criterion is the profit of the patient – if there is possible to obtain very good results using a certain method, then there is no reason for its change…
Literature:
January 10, 2002 J. Stingl