RA week 4 Flashcards
inguinal canal?
contains?
oblique passage thru lower anterior abdominal wall (4cm long in adults)
males = carries structures to/from testis + abdomen (+ ilioinguinal nerve)
females = carries round ligament of uterus from pelvis to labia majora (+ ilioinguinal nerve)
in both sexes = ilioinguinal nerve passes thru canal to exit via superficial inguinal ring
what is inguinal canal formed from?
superficial inguinal ring?
why is it not ring shaped?
function?
inguinal canal = composed of aponeurosis of external oblique
superficial inguinal ring = triangular-shaped defect (hole) in aponeurosis of eternal oblique (base formed by pubic crest)
it is triangular due to shape of strong sides of the opening - crura
crura give rise to the external spermatic fascia of the spermatic cord
what supports the crura of the superficial inguinal ring?
external oblique forms?
intracrural fibres support crura
external oblique forms anterior wall of the canal and also forms inguinal ligament in the floor of the canal
(pic = can see spermatic cord passing away from inguinal canal towards scrotum)
why is it easier to see superficial inguinal ring in males?
ilioinguinal nerve?
easier to see the superficial inguinal ring in males as spermatic cord can be followed from scrotum to abdominal wall (the point it ‘disappears’ is it passing through the superficial ring)
harder to see the superficial ring in females as round ligament of the uterus is fibrous and may blend with the wall of the canal
ilioinguinal nerve pierces posterior wall (i.e not deep inguinal ring) of the inguinal canal in both sexes then passes through canal to exit at the superficial ring
deep inguinal ring?
found?
medial to deep inguinal ring?
what does deep inguinal ring give rise to?
deep inguinal ring = oval opening in the transversalis fascia
found halfway between ASIS and pubic symphysis (1.3cm above inguinal ligament)
medial to deep inguinal ring = inferior epigastric vessels (run directly inferior to rectus abdominis, supply muscles of anterior abdominal wall)
gives rise to internal spermatic/round ligament fascia
what structures pass through deep inguinal ring?
males = contents of spermatic cord: vas deferns, genital branch of genitofemoral nerve, tesicular artery + testicular vein
females = round ligament of the uterus and genital branch of genitofemoral nerve
attachments of external oblique aponeurosis?
anterior wall of inguinal canal?
floor of inguinal canal?
roof of inguinal canal?
posterior wall of canal?
external oblique aponeurosis - passes dwon abdominal wall then rolls over itself to attach to ASIS + pubic tubercle (inguinal canal)
anterior wall = aponeurosis of external oblique (+ internal oblique in lateral ⅓rd)
floor = inferior rolled edge of external oblique aponeurosis (inguinal ligament)
roof = internal oblique + transversus abdominus
posterior wall = transversalis fascia + conjoint tendon in medial ⅓rd
why is lateral ⅓rd of anterior wall of inguinal canal also supported by internal oblique?
corresponds to where deep inguinal ring lies in posterior wall of canal
what is medial ⅓rd of posterior wall of inguinal canal supported by?
why?
what is this?
attachments?
conjoint tendon
corresponds to weak area of superficial ring in anterior wall
conjoint tendon = tendons of internal oblique + transversus abdominis combine to attach to pelvis
attachments of conjoint tendon = common insertion of internal oblique + transversus abdominus to pubic crest and pectineal line
inguinal ligament formed from?
ligament associated with inguinal ligament?
attachments?
function?
inguinal ligament formed from aponeurosis of external oblique as it rolls back on itself
lacunar ligament extends from medial end of inguinal lig - extends superoposteriorly to pectineal line (superior ramus of pubis)
lacunar ligament joints thick periosteum of pectineal line (pectineal ligament)
function = free edge of lacunar ligament forms medial edge of femoral ring (where femoral vessels pass into lower limb)
prevention of herniation of contents thru inguinal canal?
to prevent herniation the inguinal rings are not directly aligned with each other – creating an oblique canal that is more difficult for structures to pass through
walls of the canal are strengthened (in posterior wall directly posterior to superficial ring in anterior wall + in anterior wall directly anterior to deep ring in posterior wall)
when increased abdo pressure (e.g. coughing) internal oblique + transversus abdominus contract and flatten the canal
defecation + childbirth = natural squatting position with hips flexed (thighs up to abdominal wall to protect it)
hernia?
most common abdominal hernia?
types?
hernia = protrusion of tissue through wall that normally contains it
75% of abdominal hernias are inguinal
indirect = inguinal canal entered via congenital weakness in deep inguinal ring
direct = pushes through week spot in back of inguinal canal i.e. weakness of abdominal wall muscles (will reappear on cough test)
femoral = into back of femoral sheath
complication inguinal hernia?
In inguinal region = hernia is often loops of intestine
loops can become compressed or twisted (torsion) leading to loss of blood supply and necrosis
spermatic cord?
coverings?
attachments?
contents?
spermatic cord = collection of structures that pass along inguinal canal to/from the testis
3 concentric layers of fascia derived from anterior abdominal wall
begins at deep inguinal ring and ends at testis
contains: vas deferens (+artery), testicular artery + veins, cremasteric artery, genital branch of genitofemoral nerve, lymph vessels, autonomic nerves
vas deferens function?
carries sperm away from the testis towards the ejaculatory duct inside the prostate gland
coverings of spermatic cord?
females?
processus vaginalis (peritoneal diverticulum) = from L1 through abdominal wall, acquires sheath from each wall layer
passes through deep inguinal ring (transversalis fascia) = internal spermatic fascia
under transversus abdominis = no covering from this layer
through internal oblique = cremaster muscle (fascia)
through external oblique aponeurosis (this creates superficial inguinal ring) = external spermatic fascia
in females it is the same, just replace “sparmatic” with round ligament of the uterus (the genital branch of genitofemoral nerve also runs with round ligament)
spermatic cord contents + fucntions
- Vas deferens = cordlike muscular duct - transports spermatozoa from epididymis to urethra
- Testicular artery = L2 branch of abdominal aorta, supplies testes and epididymis
- Testicular veins = starts as pampiniform plexus from border of the testis but forms single vein at the level of the deep inguinal ring
- Lymph vessels = to para-aortic nodes at root of testicular artery
- Autonomic nerves = sympathetic on artery from renal or aortic plexuses
- cremasteric artery (from inf. epigastric) to cremaster fascia
- artery of vas deferens (from inferior vesical artery)
- genital branch of genitofemoral nerve (supplies cremaster muscle)
(genitofemoral nerve and artery to the cremaster muscle/fascia layer lie between the cremasteric and internal fascial layers)
genitofemoral nerve and artery to the cremaster muscle/fascia layer lie between the cremasteric and internal fascial layers
artery of the vas deferens lies deeper in the cord, close to the vas deferens to supply it
scrotum?
contains?
fascia?
musclulature?
tunica vaginalis?
outpouching of skin from abdominal wall (as sperm cannot fully mature at core body temperature)
contains: testes, epididymis + lower end of spermatic cords
fascia
superficial (camper’s) fascia = continuous with abdominal wall but fat replaced by smooth muscle - dartos
scarpa’s fascia (colles’) = attached to perineal body + membrane and ischiopubic rami
cremaster muscle = raises testes and scrotum upwards for warmth + protection
tunica vaginalis lies within spermatic fascia and is a closed off sac (remains of processus vaginalis)
(remember scarpa’s fascia called Colles’ in pubic region)
fascia of scrotum?
internal spermatic fascia = from transversalis fascia at deep inguinal ring
cremasteric fascia = internal oblique
external spermatic fascia = external oblique at superficial inguinal ring
(note = no fascial layers from transversus abdominus as processus vaginalis passes under this layer instead of through it)
where are testes formed?
embryological pathway?
males vs females?
testes formed in abdominal region but cannot create functional sperm at core body temperature
mesenchyme cells condense to form gubernaculum - travels through inguinal canal to labio-scrotal swelling
males = testes travel through inguinal canal in 7-8th foetal month, follow path of gubernaculum
female = gubernaculum stuck to uterus so ovaries stay in pelvis - round ligament travels through inguinal canal to reach labia majora
function of testes?
structure?
temperature?
epididymis function?
testes create sperm
tough fibrous capsule surrounds each testis
each lobule has 1-3 seminiferous tubules that open into rete testis
rete testis connect to epididymis via efferent ductules
testis 3*C cooler tha abdomen = dartos, cremaster + heat exchange between artery and veins aid cooling
epididymis stores sperm and becomes vas deferens (vas deferens passes through spermatic cord into pelvic cavity where it joins with duct of seminal vesicle to form ejaculatory duct - one each side)
lymphatic drainage testes + scrotum?
lymphatic drainage of the testis differs from the drainage of the scrotum
scrotum is more superficial structure= so superficial inguinal nodes
testes = para-aortic nodes (approx L2 where testicular arteries originate from aorta)
peritoneum?
layers?
between layers?
double layer?
serous lining of the abdominal cavity
parietal = inner surface of body wall
visceral = surface of organs
between layers = peritoneal cavity but this is usually a ‘potential space’ filled with coils of intestine - only becomes obvious during disease or trauma when cavity fills with blood/excess fluid
double layer of peritoneum = forms mesentery which allows movement of intestine during peristalsis but also allows passage of blood vessels to/from intestine
what is is peritoneal cavity?
movement?
releases small amount of peritoneal fluid
moves in paracolic gutters towards diaphragm where it is absorbed by small veins into venous system
innervation peritoneum?
parietal peritoneum = sensitive to pain, touch, temp and pressure
lower 6 thoracic nerves = lateral and anterior walls
phrenic nerves = central part diaphragm
obturator nerve = pelvic part
visceral peritoneum = sensitive to stretch via ANS afferent fibres
over-distention will lead to pain
mesenteries of small+large intestine sensitive to mechanical stretching
fat stores peritoneum?
Even in slender individuals there is usually some fat associated with the peritoneum
The omenta, mesentery and appendices epiplocae all act as fat stores
intra-peritoneal organs?
have mesentery (surrounded by peritoneum except at point of attachment)
- stomach
- gallbladder
- small intestine (except 2, 3, 4th parts duodenum)
- spleen
- liver
- caecum (some appendix)
- transverse + sigmoid colon
extra-peritoneal organs?
no mesentery
retro-peritoneal (partially covered in peritoneum)
- primary = kidneys + supra-renal glands
- secondary = 2, 3, 4th parts duodenum, pancreas, ascending + descending colon, upper ⅔rds rectum
infra-peritoneal (sub-peritoneal) = lower ⅓rd rectum + many pelvic organs
(primary retroperitoneal structures formed on body wall, secondary moved position during development to lie on body wall)
(abdominal and pelvic cavities are continuous with each other so parietal peritoneum extends into pelvis to cover pelvic organs – they are infra- or sub-peritoneal)
arrangement of peritoneum in abdominal cavity?
what are these?
divided by?
2 parts = greater + lesser sacs
greater sac = large space that holds the intestines
lesser sac = lies posterior to stomach and lesser omentum (allows stomach to move freely)
greater + lesser sac divided by greater omentum (large apron-like fold of visceral peritoneum that hangs down from stomach)
where is greater omentum found?
contains?
function?
after a while?
Greater omentum(GO) – suspended from greater curvature of stomach, covers anterior surface of transverse colon
contains = blood vessles, nerves, lymphatics + fatty tissue
function = “policeman” of the abdomen - if part of intestine is infected/damaged it loses its motility. The greater omentum will then be pushed over the surface of the unhealthy intestine by the healthy (more mobile) parts - so the omentum is found in areas were there is a problem with the intestine
If omentum stays over the unhealthy intestine for some time it will form connective tissue adhesions that localise the infection within the abdominal cavity and slow spread to other areas
lesser sac?
As GO passes from greater curvature of the stomach, it is a double layer
It meets + fuses with another double layer (mesentery) that has passed over the transverse colon
creates 4-layered structure that closes off part of the abdominal cavity posterior to the stomach = lesser sac
transverse colon landmark?
what are these?
used as landmark between supra-colic compartment + infra-colic compartment i.e. divides peritoneal cavity into these compartments
supra-colic compartment (foregut organs) = liver, gallbladder, stomach
infra-colic compartment (midgut) = intestines
greater omentum blood vessels?
GO carries blood vessels to supply itself + greater curvature of the stomach
- left + right gastro-omental vessels to supply GO + greater curvature of stomach
- left + right gastro-oemental veins + lymphatics
(these structures can also be called the left + right gastro-epiploic vessels)
lesser sac also called?
what is it?
also called omental bursa
portion of peritoneal cavity behind lesser omentum + stomach
what is the lesser omentum? functions?
relations of lesser sac?
free edge?
lesser omentum = double fold of peritoneum that lies between the liver and lesser curvature of the stomach
It forms the anterior wall of the lesser sac and lies anterior to the opening of the greater sac – the epiploic foramen
lesser sac is closed at lateral side by gastrosplenic ligament (between stomach + spleen); and the lienorenal ligament (between spleen + left kidney)
free edge of the lesser omentum that lies anterior to epiploic foramen carries the hepatic artery (left), bile duct (right) and hepatic portal vein (posterior)
pic A = lesser omentum passing between liver + lesser curvature of the stomach (contains fat and blood vessels)
pic B = free edge of lesser omentum when all fat and peritoneum has been removed - reveals hepatic artery + bile duct + hepatic portal vein posteriorly
epiiploic foramen?
boundaries?
function?
epiploic foramen = small gap between the free edge of lesser omentum + body wall
posterior = IVC
anterior = lesser omentum
superior = liver
this foramen allows communication between greater + lesser sacs
shows free edge of lesser omentum
arrow points to epipoloic foramen
this is not an open hole as lesser omentum rests on surface of posterior wall - it is a small gap
mesentery?
function?
just the name for double layer of peritoneum connecting to an organ - so the mesentery that connects the small intestine to body wall is called “the” mesentery or mesentery proper
function = carries vessels, nerves + lymphatics to/from most of the small intestine (jejunum, ileum) i.e. branches of superior mesenteric artery/vein
allows mobility of intestines in peritoneal cavity
other mesentery? (not mesentery proper)
function?
mesentery attached to large intestine (transverse/sigmoid colon) = mesocolons
example shown in pic is transverse mesocolon
function = carries vessels that supply transverse colon
…
retroperitoneal structures
IVC, aorta, lumbar plexus
Pic A = skin of the anterolateral abdominal wall being reflected towards the inguinal region
Pic B = major landmarks for the inguinal ligament – the anterior superior iliac spine + the pubic tubercle. In this cadaver the wall of the abdomen has been reflected so some of the intestinal coils can also be seen in the top right of the photograph
Pic A = skin of inguinal region reflected away from the body wall. The superficial fascia passes over the inguinal region to be continuous with the fascia of the thigh and perineum.
Pic B = aponeurosis of external oblique as it passes towards the pelvic bones. The aponeurosis rolls over on itself to form a tube-like shape = boundaries of the inguinal canal. What you can see in the photograph is the anterior wall of the inguinal canal, composed mainly from external oblique. External oblique attaches to the anterior superior iliac spine and the pubic tubercle to form the inguinal ligament which forms much of the floor of the inguinal canal
Pic A = superficial inguinal ring – a defect in the aponeurosis of external oblique. The forceps are passing through the superficial ring.
All of the photographs are from female cadavers. The superficial ring and the inguinal canal is more difficult to locate on a female as the structures that pass through the canal and exit the ring are very small.
Pic B = ilioinguinal nerve. In this individual the nerve is very pale in appearance – in some cadavers it will be a pink/white candy-stripe colour and easier to see.
In females the ilioinguinal nerve and the round ligament of the uterus pass through the superficial inguinal ring. The round ligament often blends with the fascia of the inguinal canal and so is difficult to identify.
Pic C = round ligament passing from deep inguinal ring into the pelvic cavity to attach to the wall of the uterus
Pic A = anterior wall of the inguinal canal and the superficial inguinal ring in a female. If you reflect the aponeurosis of external oblique you can observe the structures within the inguinal canal, as shown in photograph B.
The pointer shows the ilioinguinal nerve as it pierces through internal oblique to enter the inguinal canal. The muscle fibresof internal oblique can be seen forming part of the roof of the canal
In males, the superficial inguinal ring is easy to identify as the spermatic cord passes through the ring to carry structures to/from the testis. This is shown in photograph A.
The pathway between the abdominal cavity, the inguinal region and the scrotum is formed during development to allow the testes to descend into the scrotum. The coverings found in the wall of the spermatic cord are derived from the layers of the abdominal wall. Photograph B shows the spermatic fascia that contribute to the wall of the spermatic cord.
Photograph C shows the cord opened to reveal the vas (ductus) deferens and the testicular artery. The smaller artery to the vas deferens can also be seen to the left. The pampiniform venous plexus cannot be seen in the photograph
The skin of the scrotum is an outpouching of the skin of the abdominal wall. The fascial layers of the spermatic cord continue into the scrotum. This is shown in photograph A.
Photograph B shows the epididymis that stores sperm during sperm maturation and the testis
