inguinal canal anatomy Flashcards
describe the development of testis ?
during development , the gonads descends from the posterior abdominal wall to :
pelvis —-> in females
scrotum —–> males —> cuz testes require temperature lower than the body temperature
so initially part of the viscera in the posterior abdominal wall close to the kidneys
what is the gubernaculum?
fibromuscular structures –> connects the lower poles of the gonads
it passes through the ANTERIOR abdominal wall
to the labium majora in females
to the scrotum in males
what is the embryological structure that is responsible for guiding the descent of testis?
Gubernaculum
what precedes the descent of testis and form pathway in the inguinal canal?
processus vaginalis
what is processus vaginalis ?
parietal peritoneum
describe the pass way of parietal peritoneum / processus vaginalis?
pass through the deep inguinal ring ———–> then through the inguinal canal —-> getting out of the superficial inguinal ring ———> Scortum
then the testis will pass through these to reach the scrotum
what happens to the parietal peritoneum and what is the consequence if it doesnt happen?
the parietal peritoneum is cut off
if it doesnt get cut off = herniation will occur
what are 2 phases of testicular descent?
Trans-abdominal phase
Trans-inguinal phase
describe trans-abdominal phase?
testes descend from their LATERAL position in the abdomen to the deep inguinal ring
describe trans-inguinal phase?
the testes continue descending through inguinal canal
The guberncaulum shortens guiding the testes into the scrotum
The parietal peritoneum is closed off during this process and the :
processus vaginalis TRANSFORMS into the tunica vaginalis
what happens in females ?
instead of testes the round ligament of the uterus develops following a similar descent pathway
describe processus vaginalis?
a tubular process of peritoneum
passes into the scrotum with the descending testis
its neck usually closed at the time of birth
what happens if processus vaginalis fail to close?
hernia
what happens to the distal parts after closure?
remains as tunica vaginalis of the testis
what happens when the testes invaginate the tunica vaginalis ? ( the distal parts of processus vaginalis )
when the testes invade it it will form parietal and visceral layer
between them we have potential space containing serous fluid
what is the deep inguinal ring and what is the location of it?
a deficiency in transversalis fascia
located half an inch above the midpoint of inguinal ligament
transversus abdominis arches over the inguinal canal without forming part of its wall
describe inguinal canal?
oblique passage extending from the deep inguinal ring ( LATERALLY )
Lies parallel and superior to medial half of the inguinal ligament
superficial inguinal ring ( MEDIALLY )
opening in the external oblique aponeurosis = superficial inguinal ring
opening in the transversalis fascia = deep inguinal ring
between them a canal = inguinal canal
what are the boundaries of inguinal canal?
anterior wall
posterior wall
roof
floor
what would exist from the superficial inguinal ring?
spermatic cord
what are the coverings of spermatic cord?
Transversalis fascia
Internal oblique aponeurosis
External oblique aponeurosis
what forms the roof of inguinal canal?
arching fibers of internal oblique and transverse abdominis
the transversus abdominis is not pierced by the spermatic cord because it takes its origin from ( LATERAL ONE THIRD OF THE INGUINAL LIGAMENT )
this positioning allows the transversus abdominis to ARCH OVER the inguinal canal and form the roof and avoid pushed forward into it
and cuz of this it doesnt contribute to the anterior wall ( cuz from the lateral 1/3 of inginal ligament )
on the other hand internal oblique arise from later 2/3 of inguinal ligament so it does contribute to the anterior wall
what forms the anterior wall of inguinal canal?
formed primarily by the external oblique aponeurosis
LATERALLY : reinforced by internal oblique muscle
what forms the posterior wall of inguinal canal?
primarily by transversalis fascia —> laterally
Medially :
Conjoint tendon ( fusion of the internal oblique and transversus abdominis aponeurosis )
Reflected part of inguinal ligament ( anterior to the conjoint tendon )
what forms the floor of inguinal ligament?
iliopubic tract —-> ( thickened inferior margin of transversalis fascia ) and appear as fibrous band running parallel and posterior to inguinal ligament
under curving fibers of inguinal ligament
Lacunar ligament
what is interfoveolar ligament?
medial thickening of the deep inguinal ring
what is the content of inguinal canal?
ilioinguinal nerve in both sexes
Males : spermatic cord which is formed when the testis descend through the inguinal canal into the scrotum carrying its ducts and vessels and nerves
Females : round ligament of uterus ( help maintain the uterus in its anteverted position by exerting a forward pull ) –> attaches to connective of labia majora
what is internal spermatic fascia?
extension of transversalis fascia
what is cremasteric fascia ?
extension of internal oblique muscle
Surrounds the testes
what is external spermatic fascia ?
external oblique aponeurosis
what are the 3 arteries inside the spermatic cords?
rule of 3
3 fascia :
External spermatic –> External oblique aponeurosis
Cremasteric —> internal oblique aponeurosis
Internal spermatic —-> transversalis fascia
3 arteries :
Testicular artery from ( Aorta )
Cremasteric artery from ( inferior epigastric )
Artery to vas deferens from (inferior vesical artery)
what are nerve inside the spermatic cord?
3 nerves :
Ilioinguinal
Genital branch of genitofemoral
Sympathetic
So 3 fascia, 3 arteries, 3 nerves
what are the structure in spermatic cord ?
rule of 3
1- Vas deferens / ductus deferens
2- Pampiniform plexus ( reduce the heat from arterial blood )
3- Processus vaginalis/ lymphatic
so 3 fascia, 3 artery , 3 nerves ,3 structures
what is the lymph drainage of testis?
drain to para aortic lymph nodes round to renal vessels
why does testis drain into para aortic lymph nodes ?
because they originate from the posterior abdominal wall
So as they descend downward bring their lymph vessels with them
what is the lymphatic drainage of scrotum?
drain into superficial inguinal lymph nodes
what is cremasteric muscle ?
thin muscular layer that spreads out over the spermatic cord and testis in a series of loops
what is the origin of cremasteric muscle ?
arise in the middle of inguinal canal as continuation of the:
internal oblique muscle and its fascia
what is the function cremasteric muscle ?
draws the testis up toward the inguinal ring
Contract in response to cold temperatures —> pulling the testes closer to the body to conserve heat
Relaxes in warmer temperature allowing the testes to descend further from the body to cooldown
what is the nerve innervation of cremasteric muscle ?
innervated by genital branch of genitofemoral nerve
what are mechanisms of inguinal canal?
Flap valve mechanism
shutter mechanism
contraction of external oblique
ball valve mechanism
describe flap valve mechanism ?
deep and superficial inguinal ring in the adults are not placed one behind the other it is not straight its oblique ( act as natural barrier against herniation )
hence the canal is obliterated during the rise in intra abdominal pressure by approximation of external and internal oblique ( Which form the anterior wall )
the anterior wall will go closer to posterior wall
if it was straight whenever theres increased abdominal pressure intestinal content will herniate so this is good
describe the shutter mechanism?
internal oblique muscle which forms the anterior , posterior , roof
when it contracts it approximates the roof to the floor like a shutter
describe the mechanism of contraction of external oblique ?
increases tension on the medial and lateral crura
Resisting dilation of superficial inguinal ring
describe the valve mechanism ?
contractions of the cremaster elevates the testis and spermatic cord
to plug the superficial inguinal ring
where does hernias occur?
through weak areas of the abdominal wall
hernia is protrusion of an organ or tissue through an abnormal opening or a weakened area in the wall of cavity that normally contains it
wt forms the lining of any hernial sac?
parietal peritoneum
what are the two types hernias?
direct —–> ( Directly pushes through the abdominal wall skipping the deep inguinal ring )
indirect —-> ( goes through deep inguinal ring into superficial inguinal ring )
more than 2/3 are indirect hernias
describe the hernial sac?
hernial sac is usually narrow forming the neck and expanded external to the neck
how do you differentiate hernias?
feel the pubic tubercle
superomedial —> inguinal hernia
inferolateral —–> femoral hernia
describe normal scrotum without hernia?
prcoessus vaginalis and tunica vaginalis are obliterated ( cuz the peritoneum has been cut off )
no fluid or abdominal content in it
describe indirect inguinal hernia?
prcoessus vaginalis has remained open and not terminated
called indirect because it extends from the deep ring and follow an oblique course through the inguinal canal
usually extends into the scrotum
common in young males
aka congenital inguinal hernia
what is hydrocele?
accumulation of fluid in tunica vaginalis of the scrotum
normally in the scrotum the processus vaginalis and tunica vaginalis are obliterated and contain no fluid
what is the difference between hernia and hydrocele?
hydrocele is accumulation of fluid but NO PROTRUSION
what is no communicating hydrocele?
the processus vaginalis is obliterated so no fluid can move between the abdomen and the scroum
BUT THERES FLUID IN THE TUNICA VAGINALIS ( continuation of processus vaginalis )
what is communicating hydrocele?
the processus vaginalis is still open ( NOT OBLITERATED )
allowing fluid to move between the abdomen and the tunica vaginalis in the scrotum
what is direct / acquired inguinal hernia?
Hernial sac protrudes directly foreword without passing through the deep inguinal ring
LESS COMMON THAT INDIRECT HERNIA )
where does the neck of the sac lie in direct/acquired inguinal hernia?
medial to the inferior epigastric artery
why does direct/ acquired inguinal hernia occur?
weakness of posterior wall of the inguinal canal
( TRIANGLE OF HESSELBACH )
what is triangle of hesselbach?
anatomical region located on the anterior abdominal wall
lateral to the lateral border of rectus abdominis
what are the boundaries of triangle of hesselbach?
Rectus abdominis
Conjoint tendon + transveralis fascia
inguinal ligament
inferior epigastric artery
whati s the significance of hesselbach triangle?
Site where Direct inguinal hernia protrudes
So direct hernia —> protrude in hesselbach triangle
indirect hernia —-> go through the inguinal canal
what is the relation between inferior epigastric artery?
Direct hernia —> medial to inferior epigastric artery ( so the artery is lateral to it )
Indirect hernia —–> lateral to the inferior epigastric ( so the artery is medial to it )
what are coverings of direct hernias?
Parietal peritoneum
Extraperitoneal fat
Fascia transversalis
Conjoint tendon ( posterior wall medially )
Reflected part of inguinal ligament ( posterior wall medially )
External spermatic fascia ( From external oblique )
Dartos
Skin
Dartos and external spermatic fascia are skipped if we are not moving toward the testes
what does the direct hernia do to the conjoint tendon ?
Since the hernia is located medially it will push the conjoint tendon
what is dartos?
muscle fibers in the scrotum
what are the coverings of indirect inguinal hernia ?
parietal peritoneum
extraperitoneal fat
Internal spermatic fascia
Cremasteric fascia
external spermatic fascia
Dartos
Skin
no conjoint tendon or reflected part of inguinal ring because it is not direct and not through hesselbach
what are inguinal hernia repairs ?
Herinotomy —-> Removal of the hernial sac only
Herinorrhaphy —> herniotomy + repair of posterior wall of the inguinal canal
Hernioplasty —> herniotomy + reinforcement of the posterior wall of inguinal canal with synthetic mesh
POSTERIOR WALL IS REPAIRED
what happens to the dilated deep inguinal ring in cases of hernia?
sutured to make it smaller to prevent hernia
