basics

1. ANATOMY OF INGUINAL CANAL
Dr.Avinash.D
DNB RESIDENT (GEN.SURGERY)

3. Inguinal canal
• It is an oblique intermuscular passage in the
lower part of the anterior abdominal wall ,
Situated just above medial half of inguinal
ligament .

4. • The canals are approximately 3.75 to 4 cm
long.
• It is directed downward, forward & medially:
• Extending from deep inguinal ring to
superficial inguinal ring.

5. • Deep (Internal) inguinal ring : oval shaped opening in
fascia transversalis - Situated 1/2 inch above mid point of
inguinal ligament lateral to inferior epigastric artery .
• Superficial inguinal ring :
• Is a triangular gap in the external oblique aponeurosis .
• It is shaped like an obtuse angled triangle .
It is found within the aponeurosis of the external oblique,
immediately above the pubic crest, 1 centimeter above and
superolateral to the pubic tubercle. It has the following
boundaries—medial crura by pubic crest, lateral crura by
pubic tubercle and inferiorly by inguinal ligament

6. Inguinal canal box?

8. Anterior wall of inguinal canal
• In its whole extent
– Skin
– Superficial fascia
– External oblique aponeurosis
• In its lateral one-third
– The fleshy fibres of the internal oblique muscle

10. Roof of Inguinal Canal
• It is formed by the arched fibres of the
internal oblique and transverse abdominis
muscles.

12. Floor of the inguinal canal
• The 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).

14. The Posterior Wall
1. In its whole extent
• a. The fascia transversalis
• b. The extra peritoneal tissue
• c. The parietal peritoneum.
2. In its medial two-thirds
• a. The conjoint tendon
• b. At its medial end by the reflected part of
the inguinal ligament.

16. Structures passing through inguinal
canal
• The spermatic cord in males, or the round
ligament of the uterus in females, enters the
inguinal canal through the deep inguinal ring and
passes out through the superficial inguinal ring.
• The ilioinguinal nerve enters the canal through
the interval between the external and internal
oblique muscles and passes out through the
superficial inguinal ring.

17. Constituents of Spermatic Cord
• Vas Deferens
• Arteries
– Testicular Artery
– Cremasteric Artery
– Artery of Vas Deferens
• Pampiniform plexus of veins
• Lymph Vessels from Testis
• Genital Branch of Genitofemoral Nerve
• Sympathetic Nerve Plexus around Artery of Vas
Deferens

18. Coverings of Spermatic Cord
• The spermatic cord is ensheathed in three layers
of tissue:
• external spermatic fascia, an extension of
the innominate fascia that overlies
the aponeurosis of the external oblique muscle
• cremasteric muscle and fascia, formed from a
continuation of the internal oblique muscle and
its fascia
• internal spermatic fascia, continuous with
the transversalis fascia

20. Mechanisms maintaining integrity of
canal
Anatomical :
• 1. Obliquity of the canal as the superficial ring
&the deep ring don't lie opposite each other so
when intra-abdominal pressure increases
approximation of anterior & posterior wall
closure of the canal — flap valve mechanism
• 2. The superficial ring supported posterior by
conjoint tendon &reflected ligament.
• 3. The deep ring supported anterior by fleshy
fibers of internal oblique muscles

21. B. Physiological :
• 1.Contraction of the external oblique results in
approximation of the 2 crura of the superficial
ring - slit valve mechanism.
• 2. Contraction of the arching fibers of internal
oblique makes it straight & approximated to the
fibers of the canal like a shutter -shutter
mechanism.
• 3. Contraction of the cremastric muscle helps the
spermatic cord to plug the superficial inguinal
ring — ball valve mechanism.

22. • Disturbance of these factors - predispose to
inguinal hernia

23. Why inguinal canal ?
• Allows communication of scrotal contents
with the abdomen .
• Prevents mobile inta abdominal contents from
entering scrotum and possibility of damage .

24. Hesselbacks triangle

25. Thank you all !