inguinal region

1. The inguinal canal is an oblique passage through the
lower part of the anterior abdominal wall.
Dr M Idris Siddiqui

3.  Allow contents of the scrotum to
communicate with intra-abdominal contents
 Prevent mobile intra-abdominal contents
(e.g. intestine) from entering the scrotum
and possibly becoming damaged, while at
the same time permitting blood vessels,
nerves, lymphatics, vas deferens etc. to
supply the scrotal contents
3
Dr C Slater, Department of Human Biology, University of Cape Town

4. 4
Anterior wall
Roof
Floor
Imagine the right side inguinal canal viewed from the front as a
box with anterior & posterior walls, a roof & floor. The arrow
indicates that structures can run through it from lateral to medial
– e.g. in males it transmits the spermatic cord, and in females,
the round ligament of the uterus.
Dr C Slater, Department of Human Biology, University of Cape Town
Posterior wall

5. 5
Posterior wall
Floor
Here are the posterior wall, which has the DEEP inguinal ring
situated laterally, and the floor. (Roof and anterior wall removed).
Deep inguinal ring
Dr C Slater, Department of Human Biology, University of Cape Town

6. 6
Posterior wall
Floor
Here are the anterior wall (which has the SUPERFICIAL
inguinal ring situated medially), and the roof.
Anterior wall
Roof
Superficial inguinal ring
Dr C Slater, Department of Human Biology, University of Cape Town

7. 7
Posterior wall
Floor
Spermatic cord
exits through
the superficial
inguinal ring
Anterior wall
Spermatic cord enters the
inguinal canal through the
deep inguinal ringDeep inguinal ring
Superficial inguinal ring
Dr C Slater, Department of Human Biology, University of Cape Town

8. 8
Anterior wall
Superficial inguinal ring
The anterior wall is made up of the external
oblique muscle throughout, and is reinforced by
the
internal oblique m. laterally.
The transversus abdominus m. lies even more
laterally as part of the anterior abdominal wall.
The anterior wall is made up of the external
oblique muscle throughout, and is reinforced by
the
internal oblique m. laterally.
The transversus abdominus m. lies even more
laterally as part of the anterior abdominal wall.
Dr C Slater, Department of Human Biology, University of Cape Town

9. 9
Posterior wall
Floor
Spermatic cord
Anterior wall
The transversus abdominis and internal
oblique mm. combine to form the
CONJOINT tendon that arches over the
contents of the inguinal canal
The transversus abdominis and internal
oblique mm. combine to form the
CONJOINT tendon that arches over the
contents of the inguinal canal
The conjoint tendon attaches to
the pubic crest, reinforces the
posterior canal wall medially
and also forms the ROOF of the
canal
The conjoint tendon attaches to
the pubic crest, reinforces the
posterior canal wall medially
and also forms the ROOF of the
canal
Dr C Slater, Department of Human Biology, University of Cape Town
Conjoint tendon

10. 10
Deep inguinal ring
The posterior wall is formed by transversalis fascia (orange)
throughout and the conjoint tendon (red) medially. The wall is
particularly weak over the deep inguinal ring
Conjoint tendon medially
Dr C Slater, Department of Human Biology, University of Cape Town
Posterior wall

11. 11
FloorThe floor is formed by an incurving of the inguinal ligament, which
is part of the external oblique muscle, forming a gutter. (Medially it
forms the lacunar ligament which is not illustrated).
Dr C Slater, Department of Human Biology, University of Cape Town

12. 12
The anterior wall of the canal is formed by external oblique muscle
(orange) throughout and by internal oblique muscles
(red/black/white) laterally. This wall is weak medially because of the
“hole” in the external oblique muscle (= superficial inguinal ring).
The anterior wall of the canal is formed by external oblique muscle
(orange) throughout and by internal oblique muscles
(red/black/white) laterally. This wall is weak medially because of the
“hole” in the external oblique muscle (= superficial inguinal ring).
Anterior wall
Roof is formed by the conjoint tendon
and the meeting of the anterior and
posterior walls of the canal
Superficial inguinal ring
Dr C Slater, Department of Human Biology, University of Cape Town

13. • A horizontal line
stretching from
anterior iliac spine to
lateral margin of
rectus abdominis.
• The inguinal canal is
larger and more
prominent in men.

14. In the males, it allows structures to pass
to and from the testis to the abdomen.
In females it allows the round ligament
of the uterus to pass from the uterus to
the labium majus.
 The inguinal canal also contains blood and
lymphatic vessels and the ilioinguinal nerve in both
sexes.

16.  The canal is about 1.5 in. (4 cm) long in the adult.
 It is directed inferomedially through the inferior
part of the anterolateral abdominal wall.
 It lies parallel and superior to the medial half of
the inguinal ligament.
 Its size and form vary with age, and although it is
present in both sexes it is most well developed in
the male.

18.  It extends from the deep inguinal ring, a hole in
the fascia transversalis , downward and medially
to the superficial inguinal ring, a hole in the
aponeurosis of the external oblique muscle.
 It lies parallel to and immediately above the
inguinal ligament.
 In the newborn child, the deep ring lies almost
directly posterior to the superficial ring so that
the canal is considerably shorter at this age.
Later, as the result of growth, the deep ring
moves laterally.

21.  It is an oval opening in the fascia transversalis, lies
about 0.5 in. (1.3 cm) above the inguinal ligament
midway between the anterior superior iliac spine
and the symphysis pubis.
 KLM: located superior to the middle of the inguinal ligament
and lateral to the inferior epigastric artery.
 Gray’s: Situated midway between the anterior superior iliac
spine and the symphysis pubis c.1.25 cm above the inguinal
ligament.
 Related to it medially are the inferior epigastric vessels,
which pass upward from the external iliac vessels.
 The margins of the ring give attachment to the internal
spermatic fascia (or the internal covering of the round
ligament of the uterus).

22. It is a triangular-shaped defect in the
aponeurosis of the external oblique
muscle and lies immediately above and
medial to the pubic tubercle.
The margins of the ring, sometimes
called the crura, give attachment to the
external spermatic fascia.

24.  Anterior
 Posterior
 Superior
 Inferior

25.  Anterior wall:
 External oblique aponeurosis, reinforced laterally by the origin of the internal
oblique from the inguinal ligament.
 This wall is therefore strongest where it lies opposite the weakest part of the
posterior wall, namely, the deep inguinal ring.
 Posterior wall:
 Conjoint tendon medially, fascia transversalis laterally.
 This wall is therefore strongest where it lies opposite the weakest part of the
anterior wall, namely, the superficial inguinal ring.
 Roof or superior wall:
 Arching lowest fibers of the internal oblique and transversus abdominis
muscles
 Floor or inferior wall:
 Upturned lower edge of the inguinal ligament and, at its medial end, the
lacunar ligament.

26. 1- Spermatic cord in male or round
ligament of uterus in female.
2- Genital branch of genitofemoral
nerve (to cremasteric muscle)
3- Cremasteric artery which is branch
of inferior epigastric artery to
cremasteric muscle.

27. 1- Spermatic cord or round ligament
of uterus.
2- Internal spermatic fascia.
3- Cremasteric muscle & its fascia.
4- Genital branch of genitofemoral
nerve.
5- Cremasteric artery.
6- Ilio-inguinal nerve.

28. The inguinal ligament is the thickened,
underturned, inferior margin of the
aponeurosis of the external oblique
 It forms a retinaculum that bridges the
subinguinal space. A slit-like gap between the
medial and the lateral crura of the external
oblique aponeurosis, bridged by intercrural fibers,
forms the superficial inguinal ring

29. The inguinal ligament and iliopubic tract,
extending from the ASIS to the pubic tubercle,
constitute a bilaminar anterior (flexor)
retinaculum of the hip joint
 The iliopubic tract is the thickened inferior margin of the
transversalis fascia, which appears as a fibrous band running
parallel and posterior (deep) to the inguinal ligament The iliopubic
tract is a useful landmark during laparoscopic hernia repair .
 The retinaculum spans the subinguinal space, through which pass
flexors of the hip and the neurovascular structures serving much of the
lower limb
Inguinal ligament

31.  The inguinal canal allows structures of the
spermatic cord to pass to and from the testis to the
abdomen in the male.
 (Normal spermatogenesis takes place only if the
testis leaves the abdominal cavity to enter a cooler
environment in the scrotum.)
 In the female, the smaller canal permits the
passage of the round ligament of the uterus from
the uterus to the labium majus.

32. Medially ® lat. border of
rectus sheath.
Laterally ®inf. epigastric
artery.
Inferiorly ® inguinal
ligament..
Floor (post.) ® conjoint
tendon & fascia
transversalis.

35.  The posterior wall of the canal is particularly
weak laterally because of the deep inguinal ring
 The anterior wall opposite the deep ring is
reinforced laterally by the internal oblique m.
 A hernia (e.g. of small bowel) that comes
through the deep inguinal ring will have to travel
along the inguinal canal as it cannot push into
the reinforced layers of muscle in the anterior
wall of the canal directly opposite the deep
inguinal ring
35
Dr C Slater, Department of Human Biology, University of Cape Town

36.  The anterior wall of the canal is weak medially
where the superficial inguinal ring is situated
 The posterior wall, opposite the superficial ring,
is reinforced medially by the conjoint tendon
that is formed by fibres of the internal oblique
and transversus abdominis muscles
 Abdominal contents cannot normally force
themselves through the superficial ring directly
because of the reinforced posterior wall medially
36
Dr C Slater, Department of Human Biology, University of Cape Town

37. 37
Deep inguinal ring ↑ intra –abdominal
pressure
Spermatic cord
Superficial inguinal ring
Conjoint tendon
= areas where reinforcement is present
Reinforced
anterior
wall by
internal
oblique m.
Reinforced
posterior wall
Pressure on
anterior wall

38. 38
Deep inguinal ring ↑ intra –abdominal
pressure
Superficial inguinal ring
Conjoint tendon
Reinforced
anterior
wall
Reinforced
posterior wall
Weakness here
leads to direct
inguinal hernias
Direct hernia
S.C.
Dr C Slater, Department of Human Biology, University of Cape Town

39.  Pass through the deep ring
 Travel along the canal
 Exit the superficial ring above and medial to the
pubic tubercle (remember the inguinal ligament
attaches to the tubercle). Since the incurved
inguinal ligament forms the floor of the canal,
the contents of the canal could not emerge
below or lateral to the public tubercle (useful in
surgical diagnosis). An example is congenital
inguinal hernia.
 Coverings of indirect hernias
39
Dr C Slater, Department of Human Biology, University of Cape Town

40.  Peritoneum
 Internal spermatic fascia
(from transversalis fascia)
 Cremaster muscle & fascia
(from transversus abdominis and
internal oblique mm.)
 External spermatic fascia
(from external oblique m.)
 Superficial fascia
 Skin
40
This is a list that you
can reason out
yourself. Work out
the covering layers
based on the
abdominal wall
layers.
Dr C Slater, Department of Human Biology, University of Cape Town

41.  If the posterior wall of the canal is weakened
medially (e.g. by chronically increased intra-
abdominal pressure), it can stretch and bulge
out through the superficial ring
 The contents of the hernia do not travel
along the length of the canal but push
directly on the stretched posterior inguinal
canal wall and through the superficial ring.
 Coverings of direct hernias
41
Dr C Slater, Department of Human Biology, University of Cape Town

42.  Peritoneum
 Transversalis fascia
 Conjoint tendon
 External oblique aponeurosis
 Superficial fascia
 Skin
42
This is a list that you
can reason out
yourself. Work out
the layers based on
the anatomy. This
will facilitate your
understanding.
Dr C Slater, Department of Human Biology, University of Cape Town

43.  A potential weakness
 A design to lessen weakness:
 Oblique passage weakest areas lying some→
distance apart
 Anterior reinforcement by Int. oblique in front of
deep ring
 Posterior reinforcement by Conjoint tendon
behind superficial ring

44. On coughing/straining
(defecation, parturition etc.) →
Internal oblique and transversus
abdominis muscles contract →
flattening the roof canal is→
virtually closed

47.  The inguinal ligamen spans the subinguinal
space, through which pass flexors of the hip
and the neurovascular structures serving
much of the lower limb.
1. Two muscles: psos & iliacus
2. Two large vessels: femoral arerty & vein
3. Two nerves: femoral nerve between ilicus & psos and
lateral cutaneous nerve of thigh. This nerve pierces or
passes behind inguinal ligament one cm medial to
ASIS.

51.  The inferior epigastric vessels are important posterior
relations of the medial end of the canal. They lie on the
transversalis fascia as they ascend obliquely behind the
conjoint tendon into the posterior portion of the rectus
sheath.
 The inguinal triangle lies in the posterior wall of the
canal. It is bounded inferiorly by the medial half of the
inguinal ligament, medially by the lower lateral border of
rectus abdominis and laterally by the inferior epigastric
artery. It overlies the medial inguinal fossa and, in part,
the supravesical fossa.

52.  Pectineal
(backward)extension of
inguinal ligament to
pectineal line (pectin pubis)
 Pectineal ligament is lateral
extension of inguinal
ligament along pectineal line.
• Represents the medial triangular expansion of the inguinal ligament to the
pectineal line of the pubis.
• Forms the medial border of the femoral ring and the floor of the inguinal
canal.

53.  The lacunar ligament is a thick triangular band of tissue
lying mainly posterior to the medial end of the inguinal
ligament.
 It measures 2 cm from base to apex and is a little larger in
the male.
 It is formed from fibres of the medial end of the inguinal
ligament and fibres from the fascia lata of the thigh,
which join the medial end of the inguinal ligament from
below.
 The inguinal fibres run posteriorly and laterally to the
medial end of the pectineal line and are continuous with
the pectineal fascia.
 They form a near horizontal, triangular sheet with a curved
medial border. This edge forms the lateral border of the femoral
canal. The apex of the triangle is attached to the pubic tubercle.

54. Inconstant
Thin triangular band which
passes upwards & medially
from medial part of inguinal
ligament

56.  INGUINAL HERNIA: An inguinal hernia involves the
protrusion of a viscus through the tissues of the
inguinal region of the abdominal wall.
 Indirect inguinal hernia:An indirect hernia is defined as
arising lateral to the inferior epigastric vessels. Many
indirect hernias are related to the congenital abnormal
persistence of the vaginal process.
 Direct inguinal hernia:A direct inguinal hernia is
defined as arising medial to the inferior epigastric
vessels. Direct hernias are always caused by an
acquired weakness of the inguinal triangle in the
medial posterior wall of the canal, and frequently
extend through the anterior wall of the canal or
superficial ring.

57.  Femoral hernia:A femoral hernia protrudes
through the femoral ring. The femoral ring is
normally closed by a femoral septum of
modified extraperitoneal tissue, and is
therefore a weak spot. In females, the ring is
relatively large and subject to profound
changes during pregnancy, explaining why
femoral hernias are more common in women.
 The pubic tubercle is an important landmark in
distinguishing inguinal from femoral hernias; the
neck of the hernia is superomedial to it in inguinal
hernia, but inferolateral in the femoral form.

58.  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.

59.  Inconstant
 Thin triangular band which passes upwards &
medially from medial part of inguinal ligament
(from the pubic tubercle )reflected from the pubic
tubercle upward toward the linea alba..
 Also has some reflection from the lacunar
ligament.

60.  If the funicular process is unobliterated in the female a
small diverticulum from the peritoneum(canal of Nuck)
accompanies the round ligament in the inguinal canal.
 A peritoneal diverticulum in the embryonic lower anterior
abdominal wall that traverses the inguinal canal; in the
male it forms the tunica vaginalis testis and normally loses
its connection with the peritoneal cavity; a persistent
processus vaginalis in the female is known as the canal of
Nuck.
 Syn: Nuck's diverticulum, processus vaginalis peritonei,
vaginal process of peritoneum.

64. The gut tube can herniate into the path of the testis.
Inguinal hernias breach the weakness of the abdominal wall around the path of the testis. Indirect
inguinal hernias (A) result when a section of intestine follows the same route as the testis, pushing
the peritoneum into the bulge that it created during migration. Indirect hernias parallel the spermatic
cord and can distend the scrotum. Direct inguinal hernias (B) result when abdominal pressure
exceeds the strength of the abdominal wall medial to the superficial inguinal ring and the path of the
inferior epigastric artery. They are caused by intense pressure, such as when lifting a heavy weight
improperly, and form a bulge of the abdominal wall, typically above the root of the scrotal sac.