Transcript 22-inguinal_canal

Inguinal canal
It is an obligue passage through the lower
part of the anterior abdominal wall and is
present in both sexes.
It transmits the ilioinguinal nerve in both
sexes
In female it transmits the round ligament
from the uterus to the labia majora.
In male, It allows structures to pass to and
from the testis to the abdomen.
It is about 1.5 inch ( 4cm ) long in the adult
and extends from the deep inguinal ring
downward & medially to the superficial
inguinal ring. It lies parallel to and
immediately above the inguinal ligament.
The deep inguinal ring, is an opening
(a hole ) in the fascia transversalis. It lies
about 0.5 inch (1.3 cm ) above the inguinal
ligament midway between the anterior
superior iliac spine & the symphysis
pubis.
Related to it medially are the inferior
epigastric vessels, which pass upward
from the external iliac artery.
The margins of the ring give
attachment to the internal spermatic
fascia or the internal covering of the
round ligament of the uterus.
In the newborn child, the deep ring lies
directly posterior to the superficial
ring. So it is shorter at this age and as
the result of growth it moves laterally.
The superficial inguinal ring is a
triangular shaped defect in the
aponeurosis of the external oblique
muscle. it lies immediately above &
medial to the pubic tubercle. The
margins of the ring called the crura &
give attachment to the external
spermatic fascia.
Walls of the Inguinal Canal
Anterior wall is formed along its entire
length by the aponeurosis of the external
oblique muscle.
It is reinforsed in its lateral third by the
origin of the internal obligue from the
inguinal ligament.
This wall is strong. It lies opposite the
weakest part of the posterior abdominal
wall (deep inguinal ring ).
Posterior wall is formed along its entire
length by the fascia transversalis.
It is reinforsed in its medial third by the
conjoint tendon ( common tendon of
insertion of the internal oblique & transversus
which is attached to pubic crest. & petineal
line ).
This wall is strong. it lies opposite the
weakest part of the anterior wall, the
superficial inguinal ring.
The inferior wall or floor of the canal is
formed by the rolled –under inferior edge of
the aponeurosis of the external oblique
muscle, namely, the inguinal ligament &
at its medial end , the lacunar ligament.
The superior wall or roof of the canal is
formed by the arching lowest fibers of the
internal oblique & transversus abdominis
muscles.
Function of the inguinal canal
It allows structures of the spermatic cord
to pass to & from the testis to the
abdomen in the male.
In the female, the canal is smaller than
male it permits the passage of the round
ligament of the uterus from the uterus to
the labia majora.
In both sexes, the canal permits the
passage of the ilioinguinal nerve.
Mechanism of inguinal canal
1- It is an oblique canal with weak
superficial & deep rings.
2- The anterior wall is reinforced by the
fibers of the internal oblique muscle
immediately in front of the deep ring.
3- The posterior wall of the canal is reinforced
by the strong conjoint tendon immediately
behind the superficial ring.
4- On coughing; straining; the arching
lowest fibers of the internal obligue
& transversus abdominis muscles
flattening out the arched roof . So,
the roof compress the contents of the
canal against the floor, so, the canal
is closed.
5- In defecation & parturition ( great
straining ) the person must tend to
squatting position, the hip joint is flexed
& the anterior surfaces of the thigh are
brought up against the anterior
abdominal wall. So the anterior
abdominal wall is protected by the thighs.
The testis descends behind the
peritoneum, dragging its blood ; nerve
supply and lymphatic drainage after it.
Before the descent of the testis and
ovary from the level of L1 a peritoneal
diverticulum called the processus
vaginalis is formed.
During its passage in the deep inguinal
ring it traverses the fascia
transversalis and acquires a tubular
covering ( internal spermatic fascia ).
A band of mesenchyme extending from the
lower pole of the developing gonad through
the inguinal canal to the labioscrotal swelling
has condensed to form the gubernaculum.
From the internal oblique it takes the
cremaster muscle.
It passes under the arching of the
transversus abdominis so, it does not
acquire a covering from it.
On reaching external oblique, it
invaginates it to form the superficial
inguinal ring and acquires the external
spermatic fascia.
N.B. In the female the term
spermatic fascia is replaced
by the covering of the round
ligament of the uterus
Abdominal Herniae
The hernial sac is a pouch
( diverticulum ) of the peritoneum
and has a neck and body
The hernial contents may
consists of any structure found
within the abdominal cavity and
may be a small piece of omentum
to a viscus like kidney.
The hernial coverings are formed
from the layers of the abdominal
wall .
Indirect Inguinal Hernia
It is believed to be congenital. It is common.
The hernial sac is the remains of the processus vaginalis ( an outpouching of
peritoneum that in the fetus is responsible for the formation of the inguinal canal
The Sac enters the deep inguinal ring lateral to the inferior epigastric vessels.
On reaching the hernial sac to the superficial inguinal ring, the neck will lay in the
deep inguinal ring. The neck is narrow
The hernial sac may extend down into the scrotum or labia majora.
It is more common than a direct
inguinal hernia.
It is more common in male than
female ( 20 times ).
It is more common on the right
side ( the right testis descends
later than the left )
It is more common in young adults
and children.
Nearly one third are bilateral
The hernial sac may extend
through the superficial inguinal
ring above and medial to the pubic
tubercle.
Direct Inguinal Hernia
It makes up 15% of all inguinal hernia.
The sac bulges directly anteriorly through the posterior wall of the inguinal canal
medial to the inferior epigastric vessels.
The neck of it is wide because it is nothing more than a generalized bulge.
It is rare in women and most are bilateral. It is a disease of old men with weak
abdominal muscles.
Spermatic Cord
It is a collection of structures that pass through
the inguinal canal to and from the testis.
It is covered by 3 concentric layers of fascia
derived from the layers of the anterior
abdominal wall.
It begins at the deep inguinal ring lateral to
the inferior epigastric artery&ends at the
testis
Structures of the Spermatic Cord
1.Vas deferens
2 . Testicular artery .1
3.Testicular veins ( pampiniform plexus )
4.Testicular lymph vessels
5.Autonomic nerves, sympathetic fibers
( run with the testicular artery) from the
renal or aortic sympathetic plexuses.
Afferent sensory nerves accompany the
efferent sympathetic fibers.
6.cremasteric artery is a branch of the
inferior epigastric artery.
7.
Remains of processus vaginalis
8.
Artery of vas deferens, is a branch of
inferior vesical artery.
9.
Genital branch of the genitofemoral
nerve supplies cremaster muscle.
Vas deferens, is a cordlike structure that can be palpated between finger & thumb in the
upper part of the scrotum. It is a thick walled muscular duct that transport
spermatozoa from epididymis to the urethra.
Testicular Artery, is a branch of the abdominal aorta at the level of the 2nd lumbar vertebra. It
is long & slender and descends on the posterior abdominal wall. It traverses
the inguinal canal & supplies the testis & epididymis.
Testicular Veins, The pampiniform plexus is an extensive venous plexus which leaves the
posterior border of the testis. As it ascends, it become reduced in size so that
at about the level of the deep inguinal ring, a single testicular vein is
formed. This vein runs up on the posterior abdominal wall & drains into the
left renal vein on the left side & into the inferior vena cava on the right side.
Covering of the spermatic cord
1- External spermatic fascia is
derived from the external oblique
aponeurosis and attached to the
margins of the superficial inguinal
ring.
2- Cremasteric fascia is derived from
the internal oblique muscle.
3- Internal spermatic fascia is derived
from the fascia transversalis and is
attached to the margins of the
deep inguinal ring.
Scrotum
It is outpouching of the lower part of the
anterior abdominal wall. It contains the testes,
epididymis & the lower end of the spermatic
cords.
Its wall has the following layers:
1. skin
2. superficial fascia
3. dartos muscle( smooth m. ) replacing fatty
layer.
4. external spermatic fascia 5.
cremasteric fascia 6. internal spermatic f.
7.
tunica vaginalis which is a closed sac
invaginated from behind by the testis. It
lies within the spermatic fasciae and
covers the anterior, medial & lateral
surfaces of the testis.
Skin
It is thin, wrinkled, pigmented and forms a
single pouch.
Superficial fascia
It is continuous with the fatty & membranous
layers of the anterior abdominal wall. The fat
is replaced by smooth muscle called dardos
muscle which is innervated by sympathetic
nerve fibers & is responsible for wrinkling of
the overlying skin.
The membranous layer ( Colles’ fascia ) is
continuous in front with the membranous
layer of the anterior abdominal wall (
Scarpa’s fascia ) & behind it is attached to
the perineal body & the posterior edge of
the perineal membrane. At the sides it is
attached to the ischiopubic rami.
Both layers of the superficial fascia
contribute to a median partition that crosses
the scrotum and separates the testes from
each other.
Spermatic fasciae
They lie beneath the superficial fascia & are
derived from the 3 layers of the anterior
abdominal wall on each side.
Cremasteric muscle
It can be made to contact by stroking the
skin on the medial aspect of the thigh.
This called cremasteric reflex
.
The afferent fibers of this reflex arc travel in
the femoral branch of the genitofemoral
nerve ( L 1 &2 ) & the efferent motor fibers
travel in the genital of the genitofemoral
nerve.
The function of this reflex is to raise the
testis & scrotum upward for warmth and
for protection against injury.
Testis
It a firm, mobile organ lying within the scrotum. The left testis lies at a lower level than the
right.The upper pole of the gland is tilted forward.
Each testis is surrounded by a tough fibrous capsule ( tunica albuginea ).
Extending from the inner surface of the capsule is a series of fibrous septa that divide the
interior of the organ into lobules. Lying within each lobule are 1 to 3 coiled seminiferous
tubules. The tubules open into a network of channels called the rete testis.
Efferent ductules connect the rete testis to the upper end of the epididymis.
Normal spermatogenesis can occur only if the testes are at a temperature lower than that of the
ْabdominal cavity ( 3 C lower than the abdominal temperature ) .
Epididymis
It is a firm structure lying posterior to the
testis with the vas deferens lying on its
medial side.
It has an expanded upper end, the head,
a body and a pointed tail inferiorly.
Laterally a distinct groove lies between
the testis and the epididymis which is
lined with the inner visceral layer of the
tunica vaginalis and is called the sinus
of the epididymis .
It is a coiled tube 6 m ( 20 ft ) long and
embedded in connective tissue.
The tube emerges from the tail of the
epididymis as the vas deferens which
enters the spermatic cord.
The long length of it , allows the storage
& maturation of the sperm .
A main function of it, is the absorption
of fluid & the addition of substances to
the seminal fluid to nourish the
maturing sperm
Blood supply of testes & Epididymis
The testicular artery is a branch of the
abdominal aorta.
The testicular veins emerges from the
testis & the epididymis as a venous net
( the pampiniform plexus ) .
This plexus becomes reduced to a single
vein as it ascends through the inguinal
canal.
The right testicular vein drains into the
inferior vena cava .
The left testicular vein joins the left renal
vein.
Lymph Vessels
1- Spermatic cord
The testicular lymph vessels ascend
through the inguinal canal & pass up over
the posterior abdominal wall to reach the
lumbar ( para- aortic ) lymph nodes on
the side of the aorta at the level of the 1st
lumbar vertebra.
2- Scrotum
lymph from the skin & fascia including
the tunica vaginalis drains into the
superficial inguinal lymph nodes.
3- Testis & Epididymis
The lymph vessels ascend in the
spermatic cord & end in the lymph nodes
on the side of the aorta, para- aortic or
lumbar nodes at the level of the 1st
lumbar vertebra.
Tapping a hydrocele
Processus Vaginalis
Normally, its upper part becomes obliterated just before birth and the lower part remains as
the tunica vaginalis.
- It may persist as a preformed hernial sac for an indirect inguinal hernia.
- Its lumen remains in communication with the abdominal cavity. Peritoneal fluid
accumulates in it, forming a congenital hydrocele.
- The upper & lower ends are oblitrated leaving intermediate encysted hydrocele of the
cord.
- Inflammation of the testis cause an accumulation of the fluid within the tunica vaginalis.
Most hydroceles are idiopathic.
Varicocele
The veins of the pampiniform plexus are elongated and dilated. It is common in
adolescents and young adults. It is more of the left side. This is due to, the left
testicular vein joins the left renal vein in which the venous pressure is higher.
Rarely, malignant disease of the left kidney extends along the renal vein and blocks
the exit of the testicular vein. So, a rapidly developing left- sided varicocele should
therefore always lead one to examine the left kidney.
Malignant Tumor of the Testis
It spreads up via the lymph vessels to the para- aortic ( lumbar ) lymph nodes at
the level of L1 vertebra.
When the tumor spreads locally to involve the tissues and skin of the scrotum, the
superficial inguinal lymph nodes are involved.
Torsion of the Testis
It is a rotation of the testis around the spermatic cord within the scrotum. It is often
associated with an excessively large tunica vaginalis. It common occurs in active
young men and children. It is accompanied by severe pain. If not treated quickly,
the testicular artery may be occluded followed by necrosis of the testis.