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ANATOMY OF
INGUINAL REGION
Dr. Nabil Khouri
Department of Anatomy
JUST
MID-INGUINAL POINT
Halfway between the pubic
symphysis and the anterior superior
iliac spine.
The femoral artery crosses into the
lower limb at this anatomical
landmark.
INGUINAL LIGAMENT
A fibrous band extending from the
anterior superior iliac spine to the
pubic tubercle.
Formed by the lower border of
external oblique aponeurosis, which
is thickened and folded on itself.
INGUINAL CANAL:
About 4 cm long, oblique passage
through the lower part of the
anterior abdominal wall.
Placed parallel with, and a little
above the inguinal ligament.
Extending from the deep inguinal
ring to the superficial inguinal ring.
In neonates, the deep ring lies
almost directly posterior to the
superficial ring.
Musculo-aponeurotic tunnel
From deep ring to superficial
ring
4 cm long and 1 cm wide
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Inguinal canals – why have them?
• Allow contents of the scrotum to communicate with intraabdominal contents
• Prevent mobile intra-abdominal contents (e.g. intestine) from
entering the scrotum and possibly becoming damaged, while at
the same time allow the passage of bood vessels, nerves,
lymphatics, vas deferens etc. to supply the scrotal contents
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A Box?
Lateral
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.
Medial
Anterior wall of the canal
• formed by the aponeurosis
of the external oblique
muscle, reinforced in its
lateral third by the fibers of
origin of the internal
oblique.
• This wall is therefore
strongest where it lies
opposite the weakest part
of the posterior wall --- the
deep 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.
Lateral
Medial
Posterior Wall
of the Canal
• formed by the
transversalis fascia,
reinforced in its medial
third by the conjoint
tendon (the common
tendon of insertion of the
internal oblique and
transversus muscles)
• The wall is therefore
strongest where it lies
opposite the weakest part
of the anterior wall --superficial inguinal ring.
Conjoint tendon
The conjoint tendon
attaches to the pubic crest,
reinforces the posterior
canal wall medially and
also forms the ROOF of the
canal
Lateral
The transversus abdominis
and internal oblique mm.
combine to form the
CONJOINT tendon that
arches over the contents of
the inguinal canal
Medial
Floor
Spermatic cord
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Muhammad Ramzan Ul Rehman
Posterior wall
Posterior wall
Conjoint tendon medially
Deep inguinal ring
Lateral
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
Medial
Inferior wall or floor of the canal
• formed by the rolledunder inferior edge of
the aponeurosis of the
external oblique muscle
(the inguinal ligament)
and at its medial end
the lacunar ligament
Lateral
Medial
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 which is not
illustrated).
Floor
Superior wall or roof of the
canal
• formed by the
arching lowest
fibers of the
internal oblique
and transversus
abdominis
muscle.
Superficial inguinal ring
Lateral
Medial
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).
Superficial Inguinal Ring
• Triangular shaped defect
• Base is formed by the
pubic crest
• The crura – margins of
the ring, give origin to the
external spermatic fascia
CONTENTS OF INGUINAL CANAL:
MALE:
spermatic cord
ilio-inguinal nerve (L-1)
FEMALE:
round ligament of uterus
ilio-inguinal nerve (L-1)
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Deep inguinal ring
Spermatic cord enters the inguinal
canal through the deep inguinal ring
Lateral
Superficial inguinal ring
Spermatic cord exits
through the
superficial inguinal
ring
Medial
Floor
SPERMATIC CORD:
Collection of structures that pass
through the inguinal canal
Begins in the deep inguinal ring.
Ends in the testis.
Spermatic cord is covered by three
concentric layers of fascia derived
from the layers of anterior abdominal
wall.
CONTENTS OF SPERMATIC CORD:
Vas deferens, Artery of the vas
deference
Testicular artery
Cremasteric artery
Panpiniform plexus (testicular vein)
lymphatics
Sympathetic nerves
Genital branch of genitofemoral nerve
Processus vaginalis
Hernias
Define hernia
The protrusion of a structure from its normal cavity through an
abnormal opening
How can they be described?
Reducible
Contents easily put back
Incarcerated: Cannot be reduced
Strangulated Contents are stuck, and there is
constriction of
the tissues at the neck of the hernia, leading to reduced venous
drainage and arterial occlusion
Direct
Indirect
Lateral to inferior epigastric artery
Medial to inferior epigastric
vessel
Direct goes directly through
Hesslebach’s Triangle
Passes through processus vaginalis via
deep & superficial inguinal rings
Travels into scrotum
Congenital type
Common in males
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Inguinal hernias
• 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
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Inguinal hernias
• 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
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= areas where reinforcement is present
Deep inguinal ring
Conjoint tendon
↑ intra –abdominal
pressure
Lateral
Reinforced
anterior wall
by internal
oblique m.
Reinforced
posterior wall
Pressure on
anterior wall
Medial
Superficial inguinal ring
Spermatic cord
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Deep inguinal ring
Conjoint tendon
↑ intra –abdominal
pressure
Lateral
Reinforced
anterior wall
Reinforced
posterior wall
S.C.
Superficial inguinal ring
Weakness here
leads to direct
inguinal hernias