This presentation provides an overview of the gross anatomy of the inguinal canal, a passage in the lower abdomen that allows the spermatic cord (in males) or round ligament (in females) to pass from the abdomen to the scrotum (in males) or labia majora (in females). The presentation includes images and diagrams to help explain the anatomy of the inguinal canal

1. OKOKO, I.E. (Ph.D.)
GROSS ANATOMY OF THE INGUINAL
CANAL

2. Inguinal canal
• The inguinal canal is a short passage that extends
inferiorly and medially, through the inferior part of
the abdominal wall.
• It is superior and parallel to the inguinal ligament.

3. Inguinal canal
• It acts as a pathway by which structures can pass
from the abdominal wall to the external genitalia.
• 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
• The inguinal canal also has clinical importance.
• It is a potential weakness in the abdominal wall,
and therefore a common site of herniation

4. Inguinal Canal
• It is an oblique passage through
the lower part of the anterior
abdominal wall situated just
above the medial half of the
inguinal ligament.
• Present in both sexes
• It allows structures to pass to and
from the testis to the abdomen in
males
• In females, it permits the passage
of the round ligament of the
uterus from the uterus to the
labium majora

5. Inguinal canal
Can best be studied under the following
headings:
1. Situation
2. Shape
3. Dimension
3. Boundaries
4. Contents
5. Applied/Clinical Anatomy

6. Situation
• It is an oblique passage through the lower part of
the anterior abdominal wall situated just above
the medial half of the inguinal ligament.
• Present in both sexes

7. Shape and Size
• Tunnel shaped
• It is about 1 ½
inches or 4cm
long in the
adults
Direction:
• Downwards,
forwards and
medially

8. Inguinal Canal
• Extends from the deep
inguinal ring downward
and medially to the
superficial inguinal ring
• Lies parallel to and
immediately above the
inguinal ligament
• In the newborn child,
the deep ring lies almost
directly posterior to the
superficial ring

9. Inguinal Canal
1. Openings – 2
i – Superficial inguinal ring
ii – Deep inguinal ring

10. Inguinal canal
10
Floor
Spermatic cord
exits through
the superficial
inguinal ring
Spermatic cord enters the
inguinal canal through the
deep inguinal ring
Deep inguinal ring
Superficial inguinal ring

11. Clinically it is important to note that the opening to the
inguinal canal is located laterally to the inferior epigastric
artery

12. Deep Inguinal Ring
• Is an oval opening in the
fascia transversalis
• Lies about ½ inch
(1.3cm) above the
inguinal ligament and
midinguinal point (
midway between the
anterosuperior iliac
spine and the symphysis
pubis) lateral to the stem
of inferior epigastric
artery.
• Margins of the ring give
attachment to the
internal spermatic fascia

13. Superficial Inguinal Ring
• Triangular in shape
• Defect in the
aponeurosis of the
external oblique muscle
• Lies immediately above
and medial to the pubic
tubercle
• Its margins some times
called crura(Med & lat
crus), give attachment to
the external spermatic
fascia

14. BOUNDARIES
1. Anterior Wall
2. Posterior Wall
3. Roof (Superior wall)
4. Floor ( Inferior wall)

15. Inguinal canal-Boundaries
15
Floor
Medial
ANTERIOR WALL (which has the SUPERFICIAL inguinal ring
situated medially), and the roof.
Superficial inguinal ring
Lateral

16. Inguinal canal (POSTERIOR WALL)
16
Floor
Medial
Here is the posterior wall, which has the DEEP inguinal ring
situated laterally, and the floor. (Roof and anterior wall removed).
Deep inguinal ring
Lateral

17. Anterior Wall of Inguinal Canal
• It is formed along its
entire length by
aponeurosis of the
external oblique
muscle
• It is reinforced in its
lateral third by the
origin of the internal
oblique from the
inguinal ligament
• This wall is strongest
where it lies opposite
the weakest part of
posterior wall, that is
deep inguinal ring

18. Posterior Wall of Inguinal Canal
• It is formed along its
entire length by the
fascia transversalis
• It is reinforced in its
medial third by conjoint
tendon, the common
tendon of insertion of
internal oblique and
transversus, attached to
the pubic crest and
pectineal line
• This wall is strongest
where it lies opposite
the weakest part of the
anterior wall, that is
superficial inguinal ring

19. Inferior Wall of Inguinal Canal = floor
• It is formed by the rolled-under inferior edge of
the aponeurosis of the external oblique muscle ,
the inguinal ligament and at its medial end, the
lacunar ligament
•

20. Superior Wall of Inguinal Canal = Roof
• It is formed by the arching lowest
fibers of the internal oblique and
transversus abdominis muscles and
transversalis fascia

21. The borders of the inguinal canal.
The anterior wall of the left inguinal
canal has been removed
Conjoint
tendon

22. Summary of Boundaries
• Anterior wall: External oblique aponeurosis,
Internal oblique muscle laterally
• Posterior wall: Conjoint tendon medially,
Transversalis fascia laterally
• Roof: Transversalis fascia, internal oblique,
Transversus abdominis
• Floor: Inguinal ligament, reinforced medially by
the lacunar ligament
• Entrance: The deep ring - opening in the
transversalis fascia
• Exit: The superficial ring -a triangular slit in the
external oblique aponeurosis.

23. Functions of Inguinal Canal
• It allows structures of spermatic cord to
pass to and from the testis to the abdomen
in male
• Permits the passage of round ligament of
uterus from the uterus to the labium
majora in female

24. Contents of Inguinal canal
• Processus vaginalis - remnant of embryonic tunica
vaginalis
• Round ligament of ovary (female)
• Spermatic cord & its contents (male):
• 3 Coverings: External, Internal and Middle
Spermatic Fasciae
• 3 Arteries: Artery to Vas, Cremasteric & Testicular
arteries
• 3 Nerves: Ilio-Inguinal (L1), Genito-Femoral
(Genital Br., L2), Sympathetic
• 3 Other structures: Vas, Pampiniform Plexus,

27. A helpful mnemonic to remember inguinal canal walls
include :
MALT (2M, 2A, 2L, 2T)
Starting from superior, moving anticlockwise in order to
posterior:
Superior wall (roof): 2 Muscles
• internal oblique Muscle
• transverse abdominus Muscle
Anterior wall: 2 Aponeuroses
• Aponeurosis of external oblique
• Aponeurosis of internal oblique
Lower wall (floor): 2 Ligaments
• inguinal Ligament·
• lacunar Ligament
• Posterior wall: 2 Ts
• Transversalis fascias

28. Structures passing through the Inguinal canal
• Spermatic Cord: It is a collection of
structures that pass through the inguinal canal to
and from the testis
• It is covered with three concentric layers of fascia
derived from the layers of anterior abdominal
wall
• It begins at the deep inguinal ring lateral to the
inferior epigastric artery and ends at the testis

29. Structures of Spermatic Cord
• Vas deferens
• Testicular artery and vein
• Testicular lymph vessels
• Autonomic nerves
• Remains of Processus vaginalis
• Cremastric artery
• Artery of the vas deferens
• Genital branch of genitofemoral nerve
• Lymph vessels from the testis

30. Covering of the Spermatic Cord
• The covering of the spermatic cord are three concentric layers
of fascia derived from the layers of the anterior abdominal
wall
• Each covering is acquired as the processus vaginalis descends
into the scrotum through the layers of the abdominal wall
• External Spermatic fascia: Is derived from the external oblique
aponeurosis. It covers the cord below the superficial inguinal
ring.
• Cremasteric Fascia: Is derived from the internal oblique and
transversus abdominis muscles and therefore covers the cord
below the level of these muscles.
• Internal Spermatic Fascia: Is derived from the fascia
transversalis and covers the cord in its entire extent.

32. Hernia
Hernia — is the protrusion of an organ, viscus or
mesentery from the cavity in which it belongs
through a normal or abnormal opening.
• Types
• 1. Inguinal
• 2. Umbilical
• 3. Femoral
• 4. Hiatal/esophageal

33. Inguinal Hernia
• Inguinal hernia is an abnormal
protrusion of abdominal contents
mesentery or intestine into the inguinal
canal
• — More common in males (because of
the larger passage caused by the decent
of the testis).
• 2 types: indirect and direct

35. Indirect Inguinal Hernia
• It is the most common form of hernia
• Is believed to be congenital in origin
• The hernial sac is remains of processus vaginalis
• Enters the inguinal canal through the deep inguinal
ring lateral to the inferior epigastric vessels
• It may extend part of the way along the canal or
as far as the superficial inguinal ring

37. Indirect Inguinal Hernia
• If the processus vaginalis has undergone no
obliteration, the hernia is complete and extends
through the superficial inguinal ring down into the
scrotum or labium majus
• Under these circumstances the neck of the hernial
sac lies at the deep inguinal ring
• It is 20 times more common in young males than
females
• Is more common on the right side(the Rt. testis
descends later than the Lt. testis)

38. Direct Inguinal Hernia
• It composes about 15% of all inguinal hernias
• Common in old men with weak abdominal
muscles and rare in women
• Hernial sac bulges forward through the
posterior wall of the inguinal canal medial to
the inferior epigastric artery
• The neck of the hernial sac is wide

39. Inguinal Hernia
Indirect
Direct
young
Common in old
Age
unilateral
Usually bilateral
Bilaterally
Oval
Hemispherical
Shape
Can reach the scrotum
never
Reaches scrotum
Downwards , forwards medially
Forwards
Direction of descent
Upward, backward laterally
backward
Reduction
Laterally
Medially
Relation to inf. epigastric art.
Feel an impulse on the tip of the
finger
Feel impulse on the side finger
Superficial inguinal ring test
Hernia does not appear
Hernia appears
Deep ring test
Reduction of hernia, put thumb
over deep ring, ask patient to
cough
Skin, superfacial fascia,
Ex.sp.fascia, cremastric muscle &
fascia, Int.spermatic fascia, extra
peritoneum fat
1- Lat. To lat. Umbilical lig
Same as indirection
2- Med. To lat.
Umbilical lig
Same but instead of cremastric
muscle & fascia we have conjoint
tendon
Coverings

40. Direct Hernia Route
The hernia
sac passes
directly
through
inguinal
triangle and
may disrupt
the floor of
the inguinal
canal.

41. Indirect Hernia Route
Note:
The hernia sac
passes outside the
boundaries of
Hesselbach's
triangle(inguinal
triangle) and
follows the course
of the spermatic
cord.