Download MBBS Anatomy PPT 49 Inguinal Canal Notes

Inguinal canal

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2.2.6 Inguinal area

Surface anatomy

Inguinal Canal

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? It is an oblique intermuscular passage through the lower

part of the anterior abdominal wall

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? Present in both sexes

? It allows structures to pass to and from the testis to the

abdomen in males

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? In females it permits the passage of the round ligament

of the uterus from the uterus to the labium majus

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? Transmits ilioinguinal nerve in both sexes


Inguinal Canal

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? It is about 1 ? inches or 4cm long in the adults

? Extends from the deep inguinal ring downward

and medially to the superficial inguinal ring

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? Lies parallel to and immediately above the

inguinal ligament

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? In the newborn child, the deep ring lies almost

directly posterior to the superficial ring

Deep Inguinal Ring

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? Is an oval opening in the fascia

transversalis

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? Lies about ? inch (1.3cm) above the

inguinal ligament midway between the

anterosuperior iliac spine and the

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symphysis pubis

? Margins of the ring give attachment to the

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internal spermatic fascia

Superficial Inguinal Ring

? Is triangular in shape

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? Lies in the aponeurosis of the external

oblique muscle

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? Lies immediately above and medial to the

pubic tubercle

? Its margins give attachment to the external

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spermatic fascia


Anterior Wal of Inguinal Canal

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? Is formed along its entire length by

aponeurosis of the external oblique muscle

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? It is reinforced in its lateral third by the

origin of the internal oblique from the

inguinal ligament

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? This wall is strongest where it lies opposite

the weakest part of posterior wall, that is

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deep inguinal ring

Posterior Wal of Inguinal Canal

? Is formed along its entire length by the fascia

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transversalis

? It is reinforced in its medial third by conjoint

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tendon, the common tendon of insertion of

internal oblique and transversus, attached to the

pubic crest and pectineal line

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? This wall is strongest where it lies opposite the

weakest part of the anterior wall, that is

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superficial inguinal ring


Inferior Wal of Inguinal Canal

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? Is formed by the rolled-under inferior edge

of the aponeurosis of the external oblique

muscle called inguinal ligament and at its

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medial end, the lacunar ligament

Superior Wal of Inguinal

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Canal

? Is formed by the arching lowest fibers of

the internal oblique and transversus

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abdominis muscles
Functions of Inguinal Canal

? It allows structures of spermatic cord to

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pass to and from the testis to the abdomen

in male

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? Permits the passage of round ligament of

uterus from the uterus to the labium majus

in female

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Mechanics of Inguinal Canal

? Flap valve mechanish- oblique canal,

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deep & sup. Ing ring do not lie opposite to

each other- increased intra abdo pressure

? ant & post wall are approximated like a

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flap.

? Guarding of the inguinal rings- deep ing

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ring guarded ANTERIORLY by IOM, Sup.

Ing ring guarded posteriorly ? conjoint

tendon & reflected part of ing lig.

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Mechanics of Inguinal Canal

? Shutter Mechanism- IOM surrounds the

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canal in front, above & behind like a

flexible mobile arch. When it contracts roof

is pulled & approximated on the floor like a

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shutter

? slit- valve mechanism- contraction of EOM

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approximates the two crura of sup ing.

Ring like a slit valve , the intercrural fibers

also help.

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Mechanics of Inguinal Canal

? Ball valve Mechanism-
contraction of cremaster muscle pulls the

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testis up & sup. Ing. Ring is plugged by

spermat. Cord.

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Spermatic Cord

? It is a collection of structures that pass

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through the inguinal canal to and from the

testis

? It is covered with three concentric layers of

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fascia derived from the layers of anterior

abdominal wall

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? It begins at the deep inguinal ring lateral to

the inferior epigastric artery and ends at

the testis

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2.2.6 Inguinal area

Spermatic cord

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? 3 Fascia layers

3 Nerves

Genito-femoral nerve

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l External spermatic

fascia

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Ilio-inguinal nerve

Sympathetic

l Cremasteric fascia

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autonomic plexus

l Internal speratic fascia 3 Other structures

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? 3 Arteries

Lymphatic vessels

Ductus deferens

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l Testicular artery

Pampiniform venous

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l Cremasteric artery

plexus

l Artery to ductus

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deferens
2.2.6 Inguinal area

Spermatic cord

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Vas Deferens

? It is a cord like structure

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? Can be palpated between finger and

thumb in the upper part of the scrotum

? It is a thick walled muscular duct that

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transport spermatozoa from the epididymis

to the urethra

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Testicular Artery

? It is a branch of abdominal aorta

? It is long and slender

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? Descends on the posterior abdominal wall

? It traverses the inguinal canal and supplies

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the testis and the epididymis

Testicular Veins

? These are the extensive venous plexus, the

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pampiniform plexus

? Leaves the posterior border of the testis

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? As the plexus ascends, it becomes reduced in

size so that at about the level of deep inguinal

ring, a single testicular vein is formed

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? Drains into left renal vein on left side and inferior

vena cava on right side

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Covering of the Spermatic Cord

? The covering of the spermatic cord are

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three concentric layers of fascia derived

from the layers of the anterior abdominal

wall

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? Each covering is acquired as the

processus vaginalis descends into the

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scrotum through the layers of the

abdominal wall

Covering of the Spermatic Cord

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? External Spermatic fascia: Is derived from the

external oblique aponeurosis and attached to the

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margins of the superficial inguinal ring

? Cremasteric Fascia: Is derived from the internal

oblique muscle

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? Internal Spermatic Fascia: Is derived from the

fascia transversalis and attached to the margins

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of deep inguinal ring

Inguinal Hernia

? A hernia is the protrusion of part of the

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abdominal contents beyond the normal

confines of the abdominal wall

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? Hernial coverings are formed from the

layers of the abdominal wall through which

the hernial sac passes

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Inguinal canal


Inguinal

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? An Inguinal hernia is a

protrusion of contents of

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hernia

abdominal-cavity through

the Inguinal canal.

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? Bulges through a weak

area in the lower abdominal

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muscles.

? An inguinal hernia appears

as a bulge on one or both

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sides of the groin. An

inguinal hernia can occur

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any time from infancy to

adulthood.

? Inguinal hernias tend to

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become larger with time.

? More common in males

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? In the case of the female, the opening of the superficial

inguinal ring is smaller than that of the male.

? As a result, the possibility for hernias through the

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inguinal canal in males is much greater because they

have a larger opening and therefore a much weaker wall

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for the intestines to protrude through.

Parts of hernia

? Consists of four parts: the sac, contents of

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the sac, covering of the sac and neck.

? Hernial coverings are formed from the layers

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of the abdominal wall through which the

hernial sac passes.

? In Amyand's hernia, the content of the hernial

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sac is the vermiform appendix.

? In Littre's hernia, the content of the hernial

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sac contains a Meckel's Diverticulum.

INGUINAL (HESSELBACH'S)

TRIANGLE

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? INGUINAL (HESSELBACH'S) TRIANGLE is an area of

the anterior abdominal wall bounded by

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? Inferior epigastric vessels,
? Inguinal ligament and
? Lateral border of the rectus abdominis.

? Direct inguinal hernias leave the abdomen through this

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triangle.


? Boundaries

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? Medial border: Lateral margin of the rectus

sheath, also called linea semilunaris

? Superolateral border: Inferior epigastric

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vessels

? Inferior border: Inguinal ligament, sometimes

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referred to as Poupart's ligament

? This can be remembered by the mnemonic

RIP (as direct inguinal hernias rip directly

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through the abdominal wall).

2.2.6 Inguinal area

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Hesselbach's triangle
Two types of inguinal hernia

l

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DIRECT AND

l

INDIRECT,

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? which are defined by their relationship to the inferior

epigastric vessels.

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? Direct inguinal hernias occur medial to the inferior epigastric

vessels when abdominal contents herniate through a weak spot

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in the fascia of the posterior wall of the inguinal canal, which is

formed by the transversalis fascia.

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? Indirect inguinal hernias occur when abdominal contents protrude

through the deep inguinal ring, lateral to the inferior epigastric

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vessels; this may be caused by failure of embryonic closure of

the processus vaginalis.

? Indirect inguinal hernia.

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l Indirect inguinal hernias are congenital hernias.

? More common in males than females
? Indirect hernias are the most common type of

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inguinal hernia.

? More common on right side.
? The neck of the hernial sac lies at the deep

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inguinal ring

? Premature infants are especially at risk for indirect

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inguinal hernias because there is less time

for processus vaginalis to obliterate.

? In a male fetus, the spermatic cord and both testicles--

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starting from an intra-abdominal location--normally

descend through the inguinal canal into the scrotum,

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the sac that holds the testicles

? Sometimes the entrance of the inguinal canal at the

inguinal ring does not close as it should just after birth,

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leaving a weakness in the abdominal wall.

? Fat or part of the small intestine slides through the

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weakness into the inguinal canal, causing a hernia.

? In females, an indirect inguinal hernia is caused by the

female organs or the small intestine sliding into the

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groin through a weakness in the abdominal wall.

Direct inguinal hernias

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?

Caused by connective tissue degeneration of the

abdominal muscles, which causes weakening of

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the muscles.

?

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Common in old men with weak abdominal

muscles and rare in women

?

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The neck of the hernial sac is wide

? The hernia involves fat or the small intestine

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sliding through the weak muscles into the groin.

? A direct hernia develops gradually because of

continuous stress on the muscles.

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? One or more of the following factors can cause

pressure on the abdominal muscles and may

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worsen the hernia:

l sudden twists, pulls, or muscle strains

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l lifting heavy objects

l straining on the toilet because of constipation

l weight gain

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l chronic coughing

Indirect Inguinal Hernia

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? It is the most common form of hernia

? Is believed to be congenital in origin

? The hernial sac is remains of processus

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vaginalis

? Enters the inguinal canal through the deep

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inguinal ring lateral to the inferior epigastric

vessels

? It may extend part of the way along the canal or

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as far as the superficial inguinal ring


Indirect Inguinal Hernia

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? If the processus vaginalis has undergone no

obliteration, the hernia is complete and extends

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through the superficial inguinal ring down into the

scrotum or labium majus

? Under these circumstances the neck of the

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hernial sac lies at the deep inguinal ring

? It is 20 times more common in young males than

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females

? Is more common on the right side

Direct Inguinal Hernia

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? It composes about 15% of all inguinal hernias

? Common in old men with weak abdominal

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muscles and rare in women

? Hernial sac bulges forward through the posterior

wall of the inguinal canal medial to the inferior

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epigastric artery

? The neck of the hernial sac is wide