Inguinal canal and scrotum Flashcards
how long is the inguinal canal in adults
4cm
why is the inguinal canal particularly important in males
allows the testes to descend from the abdominal cavity into the scrotum
what nerve is carried in the inguinal canal
ilioinguinal nerve
what is carried in the inguinal canal in females
round ligament of uterus
the inguinal canal carries the round ligament of the uterus in females from the pelvis to the
labia majora
function of the inguinal canal
allows the passage of structures from abdominal cavity into inguinal region and from there towards the perineum
describe the course of the ilioinguinal nerve in the inguinal canal
travels through part of the canal and exits via the superficial ring
what forms the anterior wall of the inguinal canal
aponeurosis of external oblique
what is the superficial inguinal ring
defect in the aponeurosis of external oblique forming an opening in the inguinal canal
what shape is the inguinal ring and why
triangular
due to the shape of the strong sides of the opening - crura
what fascia arises from the edges (crura) of the superficial inguinal ring
external spermatic fascia of the spermatic cord that passes to the testes arises from the edges of the superficial ring
base of the superficial inguinal ring formed by the
pubic crest
what 2 parts of the inguinal canal does the external oblique form
anterior wall of canal
inguinal ligament in floor of canal
why is the inguinal canal easier to see in males
follow spermatic cord from scrotum to abdominal wall and point it disappears it is passing through the superficial ring
why is the superficial inguinal ring harder to see in females
round ligament of the uterus is fibrous and may blend with wall of the canal
where does the ilioinguinal nerve enter the inguinal canal
pierces the posterior wall then travels along to exit at superficial ring
what is the name of the internal entrance of the inguinal canal
deep inguinal ring
what is the deep inguinal ring
oval opening in the transversalis fascia that forms the posterior wall of the canal
the deep inguinal ring lies more ____ than the superficial ring creating an _____ passage
deep inguinal ring lies more lateral than the superficial ring, creating an oblique passage through the wall
what is the advantage of an oblique passage through the wall
makes it more difficult for structures to push through the wall (herniate)
where is the deep inguinal ring found
half way between the ASIS and the pubic symphysis
1.3cm above the inguinal ligament
what fascia is formed from the edges of the deep inguinal ring
internal fascia of the spermatic cord
what does the deep inguinal ring give rise to in females
round ligament
describe the path of the inferior epigastric vessels in relation to the deep inguinal ring
inferior epigastric vessels that run directly inferior to rectus abdominis, pass to the medial side of the deep ring
what structures pass through the deep inguinal ring in males
contents of the spermatic cord - vas deferens, genital branch of genitofemoral nerve, testicular artery and testicular vein
what structures pass through the deep inguinal ring in females
round ligament of the uterus
genital branch of genitofemoral nerve
what forms the anterior wall of the inguinal canal
aponeurosis of external oblique
how does external oblique form the anterior wall of the inguinal canal
it passes down the abdominal wall towards the pelvis then rolls over on itself to attach to the ASIS and the pubic tubercle
how is the inguinal ligament formed
the aponeurosis of the external oblique that attaches between the ASIS and the pubic tubercle thickens
what forms the floor of the inguinal canal
inferior rolled edge of external oblique aponeurosis (inguinal ligament)
medially the lacunar ligament
what forms the roof of the inguinal canal
fibres of internal oblique and transversus abdominis muscles
how does the internal oblique contribute to the inguinal canal
supports the lateral part of the anterior wall and also forms roof of canal with transversus abdominis
why is the lateral part of the anterior wall supported
corresponds to where the deep inguinal ring lies in the posterior wall of the canal
what forms the posterior wall of the inguinal canal
mainly transversalis fascia - some support from the conjoint tendon at the medial end of the canal
the conjoint tendon supports an area that corresponds to what
weak area of superficial ring in anterior wall
how is the conjoint tendon formed
common insertion of internal oblique and transversus abdominis to pubic crest and pectineal line
where does the lacunar ligament travel from the medial end of the inguinal ligament
extends superiorly and posteriorly to the pectineal line
what is the pectineal line
superior ramus of pubis
free edge of the lacunar ligament forms what
medial margin of the femoral ring
the lacunar ligament supports the medial edge of the
femoral ring
what is the femoral ring
where the femoral vessels pass into the lower limb
where does the lacunar ligament join
the thick periosteum of the pectineal line (pectineal ligament)
how is herniation through the inguinal canal prevented
the inguinal rings are offset from eachother instead of directly aligned creating an oblique canal that is more difficult for structures to pass through
where is the wall of the inguinal canal strengthened
anterior wall directly anterior to deep ring
posterior wall directly posterior to superficial ring
what happens to the canal in situations of increased abdominal pressure e.g. coughing
abdominal wall muscles contract - internal oblique and transversus abdominis contract and flatten canal
how is the inguinal canal protected during child birth or defecation
natural squatting position with hips flexed - thighs up onto abdominal wall to protect it
what is a hernia
protrusion of tissue from one area to another
75% of abdominal hernias are ___
inguinal
what often herniates in the inguinal region
loops of intestine
what is a complication of intestinal herniation
loops can become compressed or twisted (torsion) leading to a loss of blood supply and necrosis
what is an indirect hernia
inguinal canal entered via congenital weakness at deep inguinal ring
what is a direct hernia
pushes through weak spot in back of inguinal canal
what is a femoral hernia
herniation into back of femoral sheath
how can you tell if an inguinal hernia is direct or indirect
push hernia back in and occlude the deep inguinal ring and get patient to cough - if hernia reappears it is direct
tx of hernia
surgery to replace/section tissue and put in grid
the spermatic cord passes between what
deep inguinal ring and testis
the spermatic cord carries structures to and from
the abdomen and scrotum
how many layers of fascia does the spermatic cord have
3 concentric layers of fascia
what are the layers of fascia of the spermatic cord derived from
anterior abdominal wall
what is contained in the spermatic cord
vas deferens (plus artery) testicular artery and veins cremasteric artery gential branch of genitofemoral nerve lymph vessels autonomic nerves
what does the vas deferens carry
sperm away from the testis towards the ejaculatory duct inside the prostate gland
how is the inguinal canal formed
part of the peritoneal lining of the abdominal wall forms a pouch that pushes through the abdominal wall creating the inguinal canal
how are the coverings of the spermatic cord formed
peritoneal diverticulum called processus vaginalis from L1 through abdominal wall acquiring a tubular sheath from each layer
where does the processus vaginalis come from
L1
how is the internal spermatic fascia formed
passes through deep inguinal ring (transversalis fascia)
what layer does the spermatic cord acquire from the transversus abdominis
no covering from this layer - diverticulum passes under rather than through it
as the diverticulum passes through internal oblique it forms
cremaster muscle (fascia)
how is the external spermatic fascia formed
as diverticulum passes through external oblique aponeurosis - creates superficial inguinal ring
what are the 3 layers of spermatic cord fascia
internal
cremaster muscle
external
the internal spermatic fascia is continuous with what
transversalis fascia
the cremaster muscle is continuous with what
internal oblique
the external spermatic fascia is continuous with what
external oblique aponeurosis
what is the equivalent of the spermatic cord in females
round ligament of uterus
what nerve runs within the round ligament
genital branch of genitofemoral nerve
what is the vas deferens
cord-like muscular duct which transports spermatozoa from the epididymis to the urethra
where does the testicular artery come from
L2 branch of aorta
what does the testicular artery supply
testes and epididymis
describe the venous drainage of the testes
pampiniform plexus from the border of the testis forms a single vein at the level of the deep inguinal ring
at what level is a single testicular vein formed from the pampiniform plexus
at/near level of deep inguinal ring
where does lymph from testes drain
para-aortic nodes at root of testicular artery
describe the autonomic nerves in the spermatic cord
sympathetic on artery from renal or aortic plexuses
contents of the spermatic cord
vas deferens testicular artery pampiniform plexus autonomic nerves lymph vessels cremasteric artery artery of vas deferens genital branch of genitofemoral nerve
where does the cremasteric artery come from and go
from inferior epigastric artery
to cremaster fascia
where does the artery of the vas deferens come from
inferior vesical
what nerve supplies the cremaster muscle
genital branch of genitofemoral nerve
the genitofemoral nerve and artery to the cremaster muscle/fascia layer lie where
between cremasteric muscle and internal fascial layers
the artery of the vas deferens lies where in the cord
deep
why do the testes lie outside the body
sperm cannot develop at core body temperature
what is the scrotum
outpouching of skin of abdominal wall
what does the scrotum contain
testes
epididymis
lower end of spermatic cords
describe the fascial coverings of the scrotum
superficial fascia continuous with abdominal wall but fat replaced by smooth muscle
what is the smooth muscle of the scrotum called
dartos
what is scarpa’s fascia called in the perineal region
Colles’ fascia
where does Scarpa’s (colles’) fascia attach
perineal body and membrane and the ischiopubic rami
what fascial layer has the muscle fibres of dartos muscle
camper’s
what is the function of the cremaster muscle layer
moves scrotum and testes upwards towards the body wall for warmth and protection
what is the layer closest to the testis itself
tunica vaginalis - small closed sac that is all that is remaining of the embryological processus vaginalis
what are the 3 layers of the spermatic cord
external spermatic fascia
cremasteric fascia
internal spermatic fascia
the external spermatic fascia is derived from
external oblique aponeurosis
the cremaster fascia is derived from
internal oblique
the internal spermatic fascia is derived from
transversalis fascia
why is there no fascial contribution from transversus abdominis
processus vaginalis passes under this layer instead of through
where are the testes formed
abdominal region
what is the name of the embryological pathway that the testes follow to the scrotum
gabernaculum
describe the embryological pathway that the testes follow to the scrotum
descend through abdomen to inguinal region through inguinal canal and into pouch of abdominal wall skin that forms the scrotum
why does the same not happen to ovaries in females
ova can develop at core body temperature so ovaries don’t need to move away from pelvic cavity, sperm cannot
when do the testes move through inguinal canal
7th-8th month
how is the gabernaculum formed
mesenchyme cells condense to form gabernaculum through the inguinal canal to the labio-scrotal swelling
where is the gabernaculum in females
stuck to uterus
what is the name of the fascial band that extends through the inguinal canal to the labia majora
round ligament
what is the implication of the round ligament on lymphatic drainage
potential for lymph drainage to superficial inguinal nodes from the area of the uterus to which the round ligament attaches
function of the testes
create sperm
where is sperm made in testes
seminiferous tubules
each seminal vesicle lobule contains how many seminiferous tubules
1-3
what surrounds the seminal vesicle lobules and forms septa
tubica albuginea
sperm goes from the lobules to
rete testis
sperm goes from the rete testis to the epididymis via
efferent ductules
the testis are _ degrees cooler than the abdomen
3
how is temperature of testes controlled
dartos
cremaster
heat exchange between artery and veins
where is sperm stored and matured
epididymis
sperm goes from the epididymis to…
leave testes via the vas deferens
what is the path of the vas deferens
passes through the spermatic cord and into the pelvic cavity where it joins with the duct of the seminal vesicle to form the ejaculatory duct (one each side) within the prostate gland
how is the ejaculatory duct formed
vas deferens joins with duct of seminal vesicle to form ejaculatory duct in the prostate gland (one each side)
lymph from the testis and epididymis drain to
para-aortic nodes at root of testicular artery (L2)
lymph from scrotal wall and fascia drain to
superficial inguinal nodes
