ANATOMY - Abdomen p1 Flashcards
What is the peritoneal cavity?
The potential space between parietal and visceral peritoneum
what does the peritoneal cavity contain?
peritoneal fluid
3 constituents of peritoneal fluid
H2O
electrolytes
antibodies
what structure separates the 2 components of the greater sac?
transverse mesocolon aka mesentary of the transverse colon
what are the 2 main compartments of the greater sac?
supracolic compartment
infracolic compartment
where is the supracolic compartment of the greater sac?
above the transverse mesocolon
what viscera are contained in the supracolic compartment of the greater sac? (3)
spleen
liver
stomach
where is the infracolic compartment of the greater sac?
below the transverse mesocolon
what viscera are contained in the infracolic compartment of the greater sac? (3)
small intestine
ascending colon
descending colon
how is the infracolic compartment of the greater sac further divided?
into L + R infracolic spaces by mesentary of the small intestine
what structures connect the supra and infracolic compartments of the greater sac
paracolic gutters
where are paracolic gutters
lie between posterolateral abdominal wall + lateral aspect of the ascending/descending colon
where is the subphrenic recess
between the diaphragm and the liver
what separates the left and right subphrenic recesses?
falciform ligament
which is more common, a left or right subphrenic abscess? why?
Right
incr risk perf appendicitis or duodenal perf –> via R paracolic gutter
where is the lesser sac?
posterior to the stomach and lesser omentum
how is the lesser sac connected to the greater sac?
via opening in bursa = Epiploic foramen (of Winslow)
where is the epiploic foramen?
posterior to the free edge of the lesser omentum aka hepatoduodenal ligament
what is the name of the most distal portion of the peritoneal cavity in males?
retrovesical pouch
= double fold peritoneum between rectum and bladder
is the retrovesical pouch in males open or closed
closed
where is the Pouch of Douglas?
retrouterine pouch
double fold of peritoneum between the rectum and posterior wall of uterus
where is the vesicouterine pouch?
double fold perionteum
between anterior surface uterus and bladder
is the female pelvic peritoneum open or closed? why
open
uterine tubes open into peritoneal cavity
what is culdocentesis
extraction of fluid from the rectouterine pouch by inserting needle through posterior fornix vagina
use of culdocentesis
drainage pelvic abscess
extract peritoneal fluid
how does paracentesis work
needle at anterolateral abdominal wall, superior to bladder
care to avoid which artery in paracentesis?
inferior epigastric artery
how many lumbar vertebra
5
shape of lumbar VB
kidney shaped
are lumbar vertebra deeper anteriorly or posteriorly
anteriorly
shape of vertebral foramen lumbar spine
triangular
role of accessory process on lumbar spine vertebra
at base of each TP
site of mm attachment
role of mamillary process on lumbar spine vertebra
posterior surface of each superior articular process
which ligament is unique to the lumbar vertebra
iliolumbar ligaments (betw L5+S1) - strengthen lumbosacral joint
where does the iliolumbar ligament span between?
TP L5 –> ilia + pelvis
what are the 2 layers of superficial fascia below the umbilicus?
fatty superficial Campers
membranous deep Scarpas
what lies in between Campers and Scarpas fascia?
superficial aa vv nn
what are the 3 flat abdominal muscles?
IO
EO
Transversalis Abdominis
when do the flat muscles become aponeurosis>?
at the anteromedial aspect
what happens to the flat mm aponeurosis at the midline of the abdomen?
becomes linea alba
where does the linea alba expand between?
xiphoid process to the pubic symphysis
in which direction do the external oblique muscle fibres run
inferomedially
origin/insertion external oblique
5-12th rib –> iliac crest + PT
action external oblique
contralateral rotation torso
innervation external oblique muscle
thoracoabdominal T7-11
subcostal nn T12
in what direction do the internal oblique muscle fibres run?
superomedially
origin/insertion internal oblique muscle
inguinal ligament, iliac crest lumbodorsal fascia –> ribs 10-12
action internal oblique muscle
bilateral - compression of abdomen
unilateral - ipsilateral rotation torso
innervation internal oblique muscle
thoracoabdominal nerve T7-11
subcostal nn T12
Lumbar plexus
which is the deepest flat muscle of the abdomen?
transversus abdominis
in what direction do the transversus abdominis muscle fibres run in
transversely
what structures is deep to the transversus abdominis muscle
transversalis fascia
origin/insertion transversus abdominis
inguinal ligament, CC 7-12, IC+ thoracocolumbar fascia
–>
conjoint tendon, xiphoid process, linea alba + pubic crest
action transversus abdominis
compression abdominal contents
innervation transversus abdominis
thoracoabdominal nn T7-11
subcostal nn T12
lumbar plexus
what are the 2 vertical muscles
rectus abdominis
pyramidalis
what structure splits the rectus abdominis into 2?
linea alba
what is the name of the markings made by the lateral borders of the rectus abdominis?
linea semilunaris
what is the name of the fibrous strips which intersect the rectus abdominis?
tendinous intersection
origin/insertion rectus abdominis
crest of the pubic bone –> xiphoid process + CC 5-7
action rectus abdominis
assists flat muscles in compression
stabilises pelvis during walking
depresses ribs
innervation rectus abdominis
thoracoabdominal nn T7-11
is pyramidalis superficial or deep to rectus abdominis?
superficial
origin/insertion pyramidalis
pubic crest + pubic symphysis –> linea alba
action pyramidalis
tenses linea alba
innervation pyramidalis
subcostal nn T12
what is the rectus sheath comprised of?
the aponeurosis of the 3 flat mm
which muscles do the rectus sheath enclose?
rectus abdominis
pyramidalis
which mm aponeurosis comprise the anterior wall of the rectus sheath
EO
1/2 IO
which mm aponeurosis comprise the posterior wall of the rectus sheath?
1/2 IO
TA
at what point do all of the rectus sheath aponeurosis move to the anterior wall?
at arcuate line
1/2 way between umbilicus and PS
where is the midclavicular line?
middle of clavicle to mid inguinal point
where is the umbilicus
midway between xiphoid process + PS
where is the linea semilunaris
between the 9th rib to PT
where is the transpyloric line
1/2 way between jugular notch + PS
L1
where is the intertubecular line
between the superior aspects of the R and L iliac crest
midline surgical incision
through linea alba
use of midline surgical incision
accessing abdominal cavity
paramedian incision
lateral to linea alba
use of paramedian surgical incision
good access to more lateral structures e.g. kidney, spleen, adrenals
issue with paramedian incision
ligates blood vessels and nerves to muscles medial to incision –> atrophy
kocher incision
inferior to xiphoid process –> inferolaterally in parallel to R costal margin
use of kocher incision
gaining access to GB
Chevron/rooftop incision
Kocher
+ extend incision to other side of abdomen
use Chevron incision
adrenalectomy (b/l)
oesophagectomy
gastrectomy
hepatic resection
liver transplant
Mercedes Benz incision
Chevron + vertical incision + breaking xiphisternum
use Mercedes Benz incision
adrenalectomy (b/l)
oesophagectomy
gastrectomy
hepatic resection
liver transplant ***
Mcburney incision
2 perependicular lines
splits fibres of mm without cutting hence better healing
1/3 way between ASIS + umbilicus
use Mcburney incision
open appendicectomy
what are the 5 posterior abdominal wall muscles?
iliacus
psoas major
psoas minor
quadratus lumborum
diaphragm
what does psoas sign indicate
irritation to iliopsoas group mm
how is psoas sign ilicited
flex hip –> lower abdo pain
origin/insertion quadratus lumborum
iliac crest + iliolumbar ligament –> superomedially –> TP L1-4 + inferior border 12th rib
action quadratus lumborum
extends + lateral flexes vertebral column
flexes 12th rib during inspiration
innervation quadratus lumborum
anterior rami L1-4
origin/insertion psoas minor
VB T12 + L1 –> superior rami pubis aka pectineal line
action psoas minor
flexes VC
innervation psoas minor
anterior rami L1
what % of population have psoas minor
60%
origin/insertion iliacus
surface iliac fossa + ASIS –> lesser trochanter femur
action iliacus
flexes thigh
laterally rotates thigh
innervation iliacus
femoral nn L2-4
origin/insertion psoas major
TP + VB T12-L5 –> lesser trochanter femur
action psoas major
flexes thigh at hip
lateral flexion vert column
innervation psoas major
anterior rami l1-3
how is the fascia of the posterior abdominal wall named
in relation to muscle it overlies
what is the psoas fascia attached to medially
lumbar vertebraw
what is the psoas fascia continuous with laterally
thoracocolumnar fascia
how many layers to thoracocolumnar fascia (+names)
3
anterior
medial
posterior
what muscle is between anterior and medial thoracocolumnar fascia layers
quadratus lumborum
what muscles are between medial and posterior thoracocolumnar fascia layers
deep back muscles
superiorly, what structure does the thoracocolumnar fascia thicken to become?
lateral arcuate ligament
laterally, what does the posterior layer of the thoracocolumnar fascia cover?
latissimus dorsi
what cell types are the parietal and pleural peritoneum made of?
simple squamous ep cells aka mesothelium
embyrological origin - parietal peritoneum
somatic mesoderm
nn supply parietal peritoneum
somatic nn
is parietal peritoneal pain well localiesd
yes
what sensations is the parietal peritoneum sensitive to
pressure
pain
laceration
temperature
embryological origin visceral peritoneum
splanchnic mesoderm
nn supply visceral peritoneum
same autonomic nn as viscera it covers
is pain well localised on the visceral peritoneum?
no
how does visceral peritoneum pain present
referred to dermatomes
what are intraperitoneal organs
organs covered by visceral peritoneum anteriorly and posteriorly
e.g.s of intraperitoneal organs
stomach
liver
spleen
jejunum/ileum
transverse + sigmoid colon
what are retroperitoneal organs
not associated with visceral peritoneum
only covered by parietal peritoneum anteriorly
what are the 2 types of retroperitoneal organs
primarily retroperitoneal organs
secondarily retroperitoneal organs
what is a primarily retroperitoneal organ?
organ develops and remains outside parietal peritoneum
examples of primarily retroperitoneal organs (3)
oesophagus
rectum
kidneys
what is a secondarily retroperitoneal organ?
organ is initially intraperitoneal, surrounded by mesentary
throughout development, becomes retro as mesentary is fused with posterior abdominal wall
e.g.s of secondarily retroperitoneal organs (2)
ascending colon
descending colon
Mnemonic for retroperitoneal organs
SAD PUCKER
Suprarenal/adrenal glands
Aorta + IVC
Duodenum except prox 2cm + cap
Pancreas except tail
Ureters
Colon - ascending/descending
Kidneys
Eosophagus
Rectum
what is a mesentary
double layer of visceral peritoneum which connects intraperitoneal organs to the posterior abdominal wall
it provides a pathway for aa/vv/nn/LN to reach viscera from the body wall
what is a peritoneal ligament
double fold of peritoneum which connects viscera together
or viscera to the abdominal wall
what is pain referred in relation to?
embryological origin of the organ
organs originating from foregut (6)
oesophagus
stomach
pancreas
liver
gall bladder
duodenum
organs originating from midgut
duodenum distal to entrance of CBD/major papilla to junction of proximal 2/3 of transverse mesocolon
organs originating from the hindgut
distal 1/3 of the transverse colon –> anal canal
where does pain refer from retroperitoneal organs
back
where does irritation of the diaphragm refer pain to
shoulder tip
what are the 4 parts of the stomach?
cardia
fundus
body
pylorus
level of cardia of stomach
T11
What are the 3 sections of the pylorus
antrum
canal
sphincter
level of transpyloric plane
L1
where does the greater curvature of the stomach extend between?
cardiac notch –> pyloric antrum
arterial supply greater curvature stomach
branches short gastric aa
+ R+L gastro-omental aa
which ligament attaches to the lesser curvature of the stomach?
hepato gastric ligament
arterial supply lesser curvature of stomach
L gastric aa
R gastric branch of hepatic aa
what structures are superior to the stomach?
oesophagus + L dome of diaphragm
what structures are anterior to the stomach?
diaphragm
greater omentum
anterior abdominal wall
L lobe of liver
gall bladder
what structures are posterior to the stomach
lesser sac
pancreas
L kidney
L adrenal spleen
Spleen
splenic aa
T mesocolon
level of inferior oesophageal sphincter
T11
is the inferior oesophageal sphincter under voluntary or involuntary control
involuntary
role of pyloric sphincter
controls exit of chyme from the stomach
what does the pyloric sphincter contain?
smooth muscle
when does the stomach empty into the duodenum?
when intragastric pressure is greater than the resistance of the pylorus
relation of greater omentum to stomach
hangs down over greater curvature
then folds back on itself and attaches to transverse mesocolon
relation of lesser omentum to stomach
continuous with peritoneal layer of stomach
arises from the lesser curvature, ascending to attach to the liver
which sac does the stomach lie anteriorly to?
lesser sac
aa anastomoses along lesser curvature stomach
R + L gastric aa
aa anastomoses along greater curvature stomach
R + L gastro-omental aa
L + R gastric veins drain into
hepatic portal vein
short gastric veins and + L + R gastro omental veins drain into –>
SMV
L gastric aa is a branch of
coeliac trunk
R gastric aa is a branch of
proper hepatic aa
L gastro-omental aa is a branch of
splenic aa
R gastro-omental aa is a branch of
gastro-duodenal aa
parasymp inn stomach
anterior and posterior vagal trunks from vagus nn
symp inn stomach
T6-9 –> coeliac plexus via greater splanchnic nn
LN drainage stomach
gastric + gastro-omental LN
where do the gastric + gastro-omental LN drain into
coeliac LN on the posterior abdominal wall
how long is the small intestine
6.5m
what are the 3 parts of the small intestine
duodenum
jejunum
ileum
what are the 4 parts of the duodenum
superior D1
descending D2
inferior D3
ascending D4
spinal level D1 duodenum
L1
what connects D1 to the liver
hepatoduodenal ligament
which part of the duodenum is the common site of ulceration
D1
route of D1 duodenum
ascends up from pylorus of stomach
route of D2 duodenum
curves inferiorly around head of pancreas
posterior to transverse colon, anterior to right kidney
what is the major feature of D2 duodenum
major duodenal papilla aka Ampulla of Vater opening
aa supply duodenum up to the Ampulla of Vater
gastroduodenal aa
what is the gastroduodenal aa a branch of
hepatic aa
D3 duodenum route
travels to the left, crossing IVC and aorta
inferior to pancreas and posterior to SMA/V
D4 duodenum route
after crossing aorta, ascends and curves anterior to join jejunum at duodenaljejunal flexure
what special feature does D4 of the duodenum have
suspensory ligament
role of suspensory ligament of the duodenum
contraction widens angle of duodenaljejunal flexure
aa supply to duodenum distal to ampulla of Vater
inferior pancreatico-duodenal aa
vv drainage duodenum
vv follow aa
ultimately drain into hepatic portal vv
LN duodenum
pancreatoduodenal + Sup mesenteric LN
2 most common causes duodenal ulcer
h pylori
chronic NSAID use
which aa can be eroded in a duodenal ulcer
gastroduodenal aa
are the jejunum and ileum intra or retroperitoneal
intraperitoneal
role of ileocecal valve
prevents reflux of colon contents into SI
jejunum vs ileum - location
jejunum - LUQ
ileum - RLQ
jejunum vs ileum - wall thickness
jejunum - thick
ileum - thin
jejunum vs ileum - vasarecta
jejunum - longer
ileum - shorter
jejunum vs ileum - arcades/aa loops
jejunum - less
ileum - more
jejunum vs ileum - colour
jejunum - red
ileum - pink
aa supply jejunum and ileum
SMA
how does SMA supply the jejunum and ileum
SMA moves in between layers of the mesentary branching into around 20 branches
branches anastomose to form arcades/loops
from the arcades - long, straight aa arise = vasa recta
vv supply jejunum and ileum
SMV
LN jejunum and ileum
Sup mesenteric LN
what does the mesoappendix do
suspends appendix from the terminal ileum
what is the most common position of the appendix
retro-cecal
aa supply appendix
appendicular aa
what is the appendicular aa a branch of
ileocecal aa
what is the ileocecal aa a branch of
SMA
venous supply appendix
appendicular vv
inn appendix
ANS - symp (T10) and parasym
via ileocolic branch of SM plexus
LN appendix
within mesoappendix + ileocolic LN