This document provides an in-depth overview of the anatomy of the inguinal region as viewed laparoscopically. It describes key anatomical landmarks such as Cooper's ligament, the umbilical artery, and epigastric vessels that define the spaces where direct and indirect inguinal hernias occur. Understanding the complex relationships between osseofascial, vascular, and visceral structures in the preperitoneal space is essential to avoid injury during laparoscopic hernia repair.

1. Laparoscopic Anatomy of the Inguinal
Region
Since laparoscopy has been used in the treatment of patients
with inguinal hernias, new interest has developed in the anatomy of
the inguinal region of the posterior aspect of the abdominal wall.
Anatomists and laparoscopists have published interesting articles on
the surgical anatomy of this region, which they call the laparoscopic
inguinal anatomy (Claude et al, 2000).
The laparoscopic repair of the inguinal hernias is dependent on
a proper understanding of the complex anatomy of the inguinal
region (Colborn and Skandalakis, 1998).
The inguinal ligament, pubic tubercle and lacunar ligament are
not visible laparoscopically, whereas the iliopubic tract and Cooper's
ligament are seen. Exposure of the iliopubic tract, transversus
abdominis and Cooper's ligament provides the anatomical landmarks
for securing the margins of the prosthetic mesh. Identification of the
external iliac, testicular and inferior epigastric vessels and vas is
essential so that injury can be avoided (Cheslyn Curtis and Russell,
1993).
It is essential to recognize the anatomical structures of the
preperitoneal space, as seen through the laparoscope, to be able to
achieve an efficient repair.Three landmarks which are essential to
define which are Cooper's ligtment, the umbilical artery (or its
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Laparoscopic Anatomy

2. embryological stump) and the epigastric vessels coming from the
iliac arteries and veins (Condon, 1995).
These three structures together with the iliopubic tract define
the inguinal hernia space; lateral to the inferior epigastric artery is the
indirect hernia space, medially to the inferior epigastric vessels and
lateral to the umbilical artery is the triangle of Hasselbach, site of
direct hernia space, and under the iliopubic tract and above the
Cooper's ligament is the femoral hernia space (Katkoudaand
Mouiel, 1993)
The complex three-dimensional relationship of the osseofascial
vascular and visceral components of each region must be positively
identified in order to avoid injury and assure an optimal hernia repair
(Klsin, 1991).
In contrast to the external groin anatomy, the topography and
internal features of the posterior surface of the lower abdominal wall
is an area with which many general surgeons are not familiar (Klein,
1991).
The medial aspect of the inguinal region is angled inferiorly,
consequently inguinal hernia defect lies in an oblique plane relative
to a laparoscope placed in the umbilicus, whether direct or indirect
inguinal hernia. For best visualization through the umbilicus the
Laparoscope should be held towards the horizontal plane. The
inguinal anatomy with the peritoneum intact requires identifying four
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Laparoscopic Anatomy

3. structures; the inferior epigastric vessels, the obliterated umbilical
artery, the spermatic vessels and the vas deferens (Spaw et al, 1991).
The Vas Deferens
It is the long duct of the testis, it leaves the spermatic cord at
the deep inguinal ring and hooks around the lateral side of the
inferior epigastric artery and interfoveolar ligament, then it runs
backwards and downwards on the side of the wall of the pelvis
crossing the external iliac vessels, lateral umbilical ligament till it
reaches the ischial spine, where it turns medially across the terminal
part of the ureter then on the posterior surface of the urinary bladder
where it ends by joining the seminal vesicle to form the ejaculatory
duct. It is a subperitoneal structure along its whole abdominal course
(McMinn, 1990).
The Endoabdominal Fascia Transversalis
It is a fascial lining behind the abdominal muscles and in front
of the parietal peritoneum. It is the most important layer in
peritoneum of groin hernias (Nyhus et al, 1991).
The name of transversalis fascia, formerly applied to the deep
fascia covering the internal surface of the transversus abdominis
muscle, is now applied 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 these muscles (Skandalakis et al, 2000).
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Laparoscopic Anatomy

4. Transversalis Fascia Analogues
In several locations in the endoabdominal fascial sac, there are
thickenings or condensations of the fascia, which are continuous with
and integrated to the sac itself. These condensations are termed the
transversalis fascia analogues, usually are formed at points of
insertion of various muscle groups, or at points of attachment of other
fascial or aponeurotic structures into the fascial sac itself. Five
important fascia analogues are transversalis fascial sling, transversus
abdominis aponeurotic arch, the iliopubic tract, iliopectineal ligament
and the interfoveolar ligament (Nyhus et al, 1991).
Interfoveolar Ligament
This is not a true ligament. It is a thickening of the transversalis
fascia at the medial side of the internal ring. It lies anterior to the
inferior epigastric vessels (Skandalakis et al, 2000).
Figure (9) Inguinal anatomy without peritoneal covering
(Rosenberger et al 2000)
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Laparoscopic Anatomy

5. The Hasselbach Triangle
As described by Hasselbach in 1814, the bases of the triangle
were formed by the pubic pectin and the pectineal ligament. The
boundaries of this triangle as usually described today are:
• Superolaterally: the inferior epigastric vessels
• Medial: the rectus sheath
• Inferior: the inguinal ligament This is smaller than that
described by Hasselbach in 1814. Most direct inguinal hernias occur
in this area (Skandalakis et al, 2000).
Preperitoneal Fascia
The preperitoneal fascia of the groin is a specialized local
development of ordinary connective tissue framework on which
serosal layer of peritoneal cells depends on its support. Part of this
fascia is loose areolar tissue, the more superficial of which presents a
definite membranous layer, and this membranous part of the
preperitoneal fascia is sometimes mistaken for transversalis fascia
(Bendavid, 1992).
Between the two lies a variable quantity of the extraperitoneal
fat (Fowler, 1978).
This plane of preperitoneal fascia is the most important in
laparoscopic inguinal hernia repair as it is the place where the mesh
is applied and fixed (Klein, 1991).
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Laparoscopic Anatomy

6. Peritoneal Folds
The most striking lower abdominal features are two or three
vertical folds; each is directed cranially towards the umbilicus. The
midline fold is the least constant of these and when present, is the
median umbilical or embryological urachal fold. It arises from the
dome of the bladder, reaching towards the umbilicus but more
usually disappearing at about half this distance. More consistent are
folds arching from each lateral pelvic wall and containing ligaments.
These ligaments are called medial umbilical folds and are formed by
the obliterated umbilical artery, which is the terminal branch of the
anterior division of the internal iliac artery and extends to the
umbilicus. The obliterated umbilical arteries, when divided, usually
have a degree of patency. They form the inferomedial walls of the
iliac fossae. Inguinal and femoral hernias usually lie lateral to these
folds whereas obturator hernias are inferomedial (Desmond, 1997).
The Lateral Umbilical Ligament
The lateral umbilical ligament is an insignificant structure in
relation to conventional approaches to the groin hernias, but does
interfere with visualization of the inguinal region, when viewed
laparoscopically (Charles et al, 1992).
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Laparoscopic Anatomy

7. Figure (10) Peritoneal covering with deep ring (Tim Bax et al, 2007)
Preperitoneal Anatomy
The peritoneum may be separated from underlying structures
by preperitoneal blunt dissection (extraperitoneal approach) or by
incision and mobilization of peritoneal flaps (transperitoneal
approach). When the peritoneum is incised it is found to have two
distinct layers. There is a glistening and fragile superficial layer
which is relatively avascular. The deeper adherent layer is thicker and
stronger and contains a network of seemingly haphazard blood
vessels supplying the peritoneum. Although the two are separable,
they should be incised as one layer. It is also important with a staple
or suture closure of peritoneum to ensure both layers are present in
the closure. Once the peritoneum and preperitoneal fascia have been
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Laparoscopic Anatomy

8. traversed the proper preperitoneal space of Bogros, which joins the
prevesical space of Retzius in the pelvis, is entered. This well-defined
space is the correct plane of dissection. The area is relatively
avascular with only an occasional perforating vessel connecting the
transversalis fascia and the preperitoneal fascia. The blood vessels
superficial to this space originate from the epigastric and external
iliac vessels. The blood supply deep to this space originates from the
deep internal iliac vessels (Arregui etal, 1993)
Iliopubic Tract
While the epigastric artery is the beacon of laparoscopic
surface anatomy in the inguinal area, the iliopubic tract can be called
the pivot of preperitoneal anatomy. Fascia encases the entire
peritoneal cavity as a continuous sheet. It is an embryonal structure
given different names in different areas. The fascia applied to the
transversus abdominis muscle is transversalis fascia, while that
covering the psoas and iliacus is the fascia iliacus. While these two
muscle groups do not join, their relevant fascial sheets meet in a
straight line posterior to, but parallel with the inguinal ligament. This
pale fascial condensation is the iliopubic tract (Page et al, 1996).
It has also been given other names, which have caused some
confusion, e.g. the deep crural arch, the deep femoral arch and
Thompson's ligament. It extends from the anterior superior iliac spine
medially to form the lower border of the internal inguinal ring,
crossing the femoral vessels to form the anterior margin of the
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Laparoscopic Anatomy

9. femoral sheath. The tract curves around the medial surface of the
femoral sheath to inserts just lateral to Cooper's ligament. The fascia
and tract do not merge with the inguinal ligament and this can easily
be demonstrated during an anterior abdominal wall dissection where
an instrument can be passed horizontally between the two structures
Figure (11) Site of direct and indirect hernia (Tim Bax et al, 2007)
Perhaps the most prominent and most easily located areas of
the iliopubic tract are medially where it forms the roof of the femoral
canal and immediately lateral to the epigastric artery where it forms
the floor of the internal ring. The presence of the iliopubic tract as
such a distinct structure redefines the base of Hesselbach's triangle,
so that, from a laparoscopic view point, the iliopubic tract replaces
the inguinal ligament as the floor of that triangle. Inguinal hernias are
located above the iliopubic tract and femoral hernias below it. Direct
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Laparoscopic Anatomy

10. hernias occur within Hesselbach's triangle and indirect hernias are
lateral to the epigastric artery (Desmond, 1997).
The Deep Inguinal Ring
Is situated in the transversalis fascia, midway between the
anterior superior iliac spine and the symphysis pubis, about 1, 25 cm
above the inguinal ligament. It is related above to the arched lower
margin of transversus abdominis, and medially to the inferior
epigastric vessels and the interfoveolar ligament, when present
(McMinn, 1990)
.
Figure (12) The transversals fascia (Tim Bax et al, 2007)
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Laparoscopic Anatomy

11. It is inverted u-shaped ring, composed of thickened
transversalis fascia, suspended by two pillars, medial and lateral to
the posterior aspect of the transversus abdominis muscle. It lays
opposite a point one finger breadth above the mid point of inguinal
ligament (McMinn, 1990).
Floor Of Inguinal Canal
Between the iliopubic tract and the arching edge of the
transversalis is the floor or posterior wall of the inguinal canal. The
internal ring perforates the transversalis fascia laterally. The medial
edge of the deep ring has a prominent crescentic shape concave
laterally and is called the interfoveolar ligament, formed by the
transversalis fascia, which splits to encompass the epigastric vessels
near this free edge. The lateral aspect of the iliopubic tract can then
be seen to join with the transversus abdominis muscle to form the
lateral boundaries of the internal ring. The musculoaponeurotic
transversus abdominis then arches over the internal ring and
Hasselbach's triangle to insert medially into the pubis anterior to the
rectus abdominis muscle. The floor of the inguinal canal is formed in
most patients by the transversus abdominis aponeurosis, which
extends to insert onto Cooper's ligament but can be quite variably
attenuated, sometimes leaving only the thin, transparent, and weak
transversalis fascia intervening between the intra-abdominal Forces
and the non supporting external oblique (Arregui et at, 1993).
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Laparoscopic Anatomy

12. Below the medial part of the iliopubic tract lies a triangular
area also bounded laterally by the external iliac vein and inferiorly by
Cooper's ligament, which is a glistening white structure running
along the anterosuperior border of the superior pubic ramus. It is
always easy to locate and is even more prominent than the medial
end of the iliopubic tract. The femoral ring is the upper end of the
femoral canal and lies medial to the external iliac vein. It is bounded
medially by fascia iliacus and the underlying reflected portion of
inguinal ligament, with Cooper's ligament on the pectineal line as the
inferior margin and the iliopubic tract as the upper margin. A discrete
pad of adipose tissue and sometimes a lymph node forms a plug in
the femoral ring when there is no femoral hernia (Desmond, 1997).
Vessels of the Inguinal Area
1. Epigastric vessels
The epigastric artery and vein are the largest of these and are
easily located. The artery lies lateral to the vein as both precede
superomedially toward the rectus muscle, which is reached well
below the level of the arcuate ligament which marks the lower end of
the posterior rectus sheath. The first epigastric branch is a
communicating obturator branch which drops down over the superior
pubic ramus to anastomose with the obturator vessels immediately
beneath this bone. The communicating obturator artery is usually less
obvious than the vein but when large, is called an aberrant obturator
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Laparoscopic Anatomy

13. artery. A pubic branch passes horizontally below the iliopubic tract
towards the pubic tubercle and cave of Retzius. The cremasteric
vessels branch forwards and immediately enter the inguinal canal
which is only seen if the epigastric vessels are mobilized. The
rectusial branches given off when the lateral edge of the rectus is
reached are the last visualized branches of the epigastrics, between
these and the cremastric branches the epigastric artery in particular is
very elastic and easily manipulated. A small artery to the vas is
usually visible and can easily be damaged during mobilization of an
indirect hernial sac. It is a branch of the internal iliac artery.
2. Gonadal vessels
Testicular arteries are solitary and always difficult to separate
from the accompanying gonadal veins. Proximally, the number of
testicular veins is reduced, so that just one or two prominent gonadal
veins are evident several centimeters proximal to the deep ring
(Desmond, 1997).
3. External iliac vessels
The external iliac artery runs along the pelvic brim on the psoas
muscle (retro-peritoneal) and passes beneath the inguinal ligament to
enter the femoral sheath. Its two branches are given just above the
inguinal ligament, the inferior epigastric artery and the deep
circumflex iliac artery.
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Laparoscopic Anatomy

14. Figure (13) Spermatic vessels and vas and inferior epigastric vessels
(Tim Bax et al, 2007)
The external iliac vein enters the abdomen on the medial side
of the artery. Over the sacroiliac joint each is joined by the internal
iliac vein to form the common iliac vein (Skandalakis et al., 2004).
Nerves In The Inguinal Area
The nerves in this area include the femoral nerve which lies in
a groove between psoas and iliacus muscles and is not seen during
normal dissection in this region. The nerves assume great importance
in a laparoscopic hernia repair, mainly because they are not easily
seen but are readily traumatized by dissection, staple or suture. Even
the edge of a mesh can cause sensory nerve irritation. The two most
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Laparoscopic Anatomy

15. relevant of these nerves are the genitofemoral and the lateral
cutaneous nerve of the thigh. The lateral cutaneous nerve lies on the
iliacus muscle and is found approximately midway between the
anterior superior iliac spine and epigastric vessels as it passes deep to
the fascia iliacus and below the iliopubic tract. It has the thickness of
a match and is only visualized after dissecting away fascia iliacus.
Injury to this nerve results in either a sensory deficit in the
posterolateral thigh or pain in this area on movement (MacFadyen,
1992).
The genitofemoral nerve is located beneath the fascia iliacus
between the spermatic vessels and the external iliac artery. It
bifurcates close to the deep inguinal ring, the femoral branch enter
the femoral sheath to supply sensation to a small area below the
inguinal ligament. The genital branch passes from the anterior
surface of the external iliac artery to pierce fascia iliacus and enter
the inguinal canal where it lies on the posteroinferior aspect of the
spermatic cord. It supplies sensation to lateral scrotal skin or labium
majus. Both branches are most vulnerable near the dorsal margin of
the deep inguinal ring lateral to or beneath the spermatic cord
(Kraus, 1994).
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Laparoscopic Anatomy

16. Figure (14) Inside of the inguinal area is traversed by several lumber nerves.
(Tim Bax et al, 2007)
Il = Ilioinguinal nerve
GF = Genitofemoral nerve
LFC= Lateral cutaneous femoral nerve
Triangle of Doom
The vas deferns enters the internal ring from an inferiomedial
direction, while the testicular vessels enter from the superior path.
This gap between the two has been termed the "triangle of Doom".
An area where no staples or sutures should be placed in order to
Avoid any major vascular injuries, where in this triangle the iliac
vessels are situated (Skandalakis et al, 2000).
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Laparoscopic Anatomy

17. Square of Doom
Katkhouda and Mouiel (1993), stated that; the triangle of
doom should be extended laterally to the psoas muscle where two
nerves of great importance are found: the lateral femorocutaneous
and the genitofemoral nerve; these two nerves should be kept in mind
when placing sutures or staples laterally on the psoas in order to
avoid neuromas or hyposthesia of the groin. This area described as
the "square of doom" is located between the vas medially and the
iliopubic tract superiorly.
Triangle of Pain
It is bounded by:
• Lateral border: reflected peritoneum
• Inferolateral border: iliopubic tract
• Superomedial border: gonadal vessels It contains the
following nerves:
• Lateral femoral cutaneous nerve
• Ant femoral cutaneous nerve
• Femoral branch of genitofemoral nerve
• Femoral nerves (Skandalakis et al, 2000)
Circle of Death
Formed of anastomosis between following arteries
• Common iliac artery and its two terminal divisions
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Laparoscopic Anatomy

18. • Internal iliac artery and obturator artery which gives
aberrant obturator artery.
. External Iliac Artery which gives rise to inferior epigastric
artery
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Laparoscopic Anatomy