ANATOMY - Abdomen p2 Flashcards
Role of cecum
Reservoir for chyme
Where is the cecum in the abdomen
RIF
is the cecum intra or retroperitoneal
intraperitoneal
aa supply cecum
anterior + posterior cecal aa
what are the cecal arteries branches of
ileocolic aa
what is the ileocolic aa a branch of
SMA
vv drainage cecum
ileocolic vv
where do the ileocolic vv drain into
SMV
inn cecum
ileocolic branch of superior mesenteric plexus
LN drainage cecum
ileocolic LN
what % of intestinal volvuli are cecal
10%
length of colon
1.5m
what are the 4 parts of the colon
ascending
transverse
descending
sigmoid
is the ascending colon intra or retroperitoneal
retroperitoneal
when does the ascending colon becomes the transverse colon
at the hepatic flexure
where does the transverse colon run between
hepatic flexure –> splenic flexure
how and where is the transverse colon attached to the diaphragm
at splenic flexure
via the phrenicocolic ligament
is the transverse mesocolon intra or retroperitoneal
intraperitoneal
is the descending colon intra or retroperitoneal
retroperitoneal
what structure is the descending colon anterior to
L kidney
how long is the sigmoid colon
40 cm
where does the sigmoid colon run between
iliac fossa –> S3
how is the sigmoid colon attached to the posterior pelvic wall
sigmoid mesocolon
4 features of Large intestine that differs it from Small intestine
omental appendices
teniae coli
haustra
larger diameter
what are the omental appendices
found in LI
small pouches of peritoneum filled with fat
what are teniae coli
found in LI
3 strips of MM running longitudinally
what are haustra
found in LI
when the teniae coli contract - shorten bowel –> sacculations aka haustra
structures anterior to the ascending colon (3)
SI
greater omentum
anterior abdominal wall
structures posterior to the ascending colon (5)
iliacus
quadratus lumborum
R kidney
iliohypogastric + ilioinguinal nn
structures anterior to the transverse colon (2)
greater omentum
anterior abdominal wall
structures posterior to the transverse colon (2)
SI
pancreas head
structures anterior to the descending colon (3)
small intestine
greater omentum
anterior abdominal wall
structures posterior to the descending colon (5)
L kidney
iliacus
quadratus lumborum
iliohypogastric + ilioinguinal nn
structures anterior to the sigmoid colon (3)
bladder
ureters
upper vagina
structures posterior to the sigmoid colon (3)
rectum
sacrum
ilium
what is the marginal aa of Drummond
an anastomoses of terminal branches of the IMA + SMA which provides collateral blood supply to the colon and from which vasa recta arise
middle colic aa, R colic aa and ileocolic aa arise from
SMA
l colic aa and sigmoid aa arise from
IMA
ileocolic vv and R colic vv drain into
SMV
L colic vv and sigmoid vv drain into
IMV
innervation of the midgut colon (A + prox 2/3 T colon)
superior mesenteric plexus
innervation of the hindgut colon (distal 1/3 T colon, descending + sigmoid)
inferior mesenteric plexus
sympathetic component of inferior mesenteric plexus
lumbar splanchnic nn
parasympathetic component of inferior mesenteric plexus
pelvic splanchnic nn
which LN drain the ascending + transverse colon
superior mesenteric LN
which LN drain the descending and sigmoid colon
inferior mesenteric LN
journey of Lymphatic drainage from colon to thoracic duct
Sup + inf mesenteric LN –> intestinal lymph trunks –> cisterna chyli –> thoracic duct
role of rectum
temporary storage of faeces
spinal level at which rectum begins
S3
how is the rectum distinctive from the rest of the colon? (3)
no taenia coli
no haustra
no ommental appendices
what are the 2 main flexures of the rectum
sacral flexure
anorectal flexure
sacral flexure
AP curve with concavity anteriorly
following the curve of the sacrum/coccyx
anorectal flexure + role
AP curve with convexity anteriorly
faecal continence
which muscle tone forms the anorectal flexure
puborectalis mm
what are the 3 lateral flexures of the rectum called
superior
intermediate
inferior
what are the 3 lateral flexures of the rectum formed by
transverse folds of the internal rectal wall
ampulla of the rectum - where + fct
final segment
relaxes to accommodate faeces
peritoneal coverings of rectum - superior 1/3
anterior and lateral aspects covered
peritoneal coverings of the rectum - middle 1/3
anterior aspect only covered
peritoneal coverings of the rectum - inferior 1/3
no peritoneal covering
structures anterior to the rectum in the male (6)
retrovesical pouch
sigmoid colon
ileum
bladder
prostate
seminal vesicles
structures anterior to the rectum in females (5)
rectouterine pouch
sigmoid colon
ileum
vagina
cervi x
structures posterior to the rectum (5)
sacrum + coccyx
piriformis
coccygeus
levator ani
sacral plexus
3 aa supplying the rectum
superior rectal aa
middle rectal aa
inferior rectal aa
superior rectal aa is a branch of
IMA
middle rectal aa is a branch of
internal iliac aa
inferior rectal aa is a branch of
internal pudendal aa
which 3 veins drain the rectum
superior rectal vv
middle rectal vv
inferior rectal vv
superior rectal vv drains into
portal venous system
middle rectal vein drains into
systemic system
inferior rectal vein drains into
systemic system
how do the rectal veins anastomose
via the portocaval anastomoses between the portal system and systemic system
sympathetic inn rectum
lumbar splanchnic nn
superior + inferior hypogastric plexuses
parasympathetic inn retum
S2-4 via pelvic splanchnic nn and inferior hypogastric plexus
visceral afferent/sensory inn rectum
follows parasymp
LN drainage rectum
pararectal LN
also low rectum to internal iliac LN
where do the pararectal LN drain into
inferior mesenteric LN
role of anal canal
defecation + maintaining faecal continence
where is the anal canal
within the anal triangle of the perineum
between the R+L ischioanal fossae
how long is the anal canal
4cm
where is the internal anal sphincter
surrounding the upper 2/3 of the anal canal
what is the internal anal sphincter made of?
involuntary circular SM
where is the external anal sphincter
surrounding the lower 2/3 of the anal canal
what is the external anal sphincter made of
voluntary SM
what muscle does the external anal sphincter blend with
puborectalis muscle
what structure lies at the junction of the anal canal and rectum
anorectal ring
mm ring
what forms the anorectal ring
fusion of internal anal sphincter, external anal sphincter + puborectalis mm
what cell type is the superior aspect of the anal canal
columnar epithelium
what are anal columns
mucosaorganised into longitudinal folds
what structure joins at the end of the anal columns
anal valves
what are anal sinuses
pouches above the anal valves which contain glands which secrete mucus
what important landmark do the anal valves form
dentate/pectinate line
embryological origin of anal canal above pectinate line
hindgut
embryological origin of anal canal below pectinate line
ectoderm of proctodeum
cell lining of anal canal below pectinate line
non-keratinised stratified squamous ep
when does the cell lining change from the lining below the pectinate line of the anal canal to the skin of the anus
intersphincteric groove
structures anterior to the anal canal in males (4)
perineal body
urogenital diaphragm
urethra
bulb of penis
structures anterior to the anal canal in females (3)
perineal body
urogenital diaphragm
vagina
structures posterior to the anal canal (2)
sacrum/coccyx
anococcygeal ligament
structures lateral to the anal canal (1)
ischioanal fossae
aa supply to the anal canal ABOVE the dentate line
superior rectal aa (which anastomose w/ middle rectal aa branches)
aa supply to the anal canal BELOW the dentate line
inferior rectal aa (which anastomose w/ middle rectal aa branches)
vv supply to anal canal ABOVE the dentate line
superior rectal vv
vv supply to the anal canal BELOW dentate line
inferior rectal vv
nn supply to the anal canal ABOVE dentate line
inferior hypogastric plexus (visceral)
only sensitive to stretch
nn supply to the anal canal BELOW dentate line
inferior rectal nn - somatic
sensitive to pain, temp, touch, pressure
LN drainage anal canal ABOVE dentate line
internal iliac LN
LN drainage anal canal BELOW dentate line
superficial inguinal LN
what is the largest gland in the human body
liver
function of liver
synthesis bile
glycogen storage
clotting factor production
detoxification
which region of the abdomen is the liver in
predominantly R hypogastrium
also epigastric
extends in L hypogastrium
what are the 2 surfaces of the liver
diaphragmatic (anterosuperior surface)
visceral (posteroinferior surface)
which part of the diaphragmatic surface of the liver is not covered in peritoneum
bare area
hence is in direct contact with the diaphragm
which parts of the visceral surface of the liver are not covered in peritoneum
gall bladder fossa
porta hepatis
which organs lie in contact with the visceral surface of the liver (8)
R kidney
R adrenal
R colonic flexure
T colon
D1
GB
oesophagus
stomach
4 types of ligaments attached to the liver
falciform ligament
triangular ligaments
coronary ligaments
lesser omentum
where does falciform ligament run between
anterior surface liver –> anterior abdominal wall
what does the free edge of the falciform ligament contain and what is this a remnant of?
ligamentum teres - remnant of umbilical vein
where do the triangular ligaments run between
from liver to diaphragm
where do the coronary ligaments run between
superior surface of liver to inferior surface of diaphragm
what does the lesser omentum attach the liver to
stomach (lesser curvature) + D1 via hepatoduodenal ligament + hepatogastric ligament
how is the posterior surface of the liver secured to the IVC?
via hepatic vv + fibrous tissue
what are the 3 recesses associated with the liver?
subphrenic
subhepatic
Morisons pouch
where is the subphrenic recess
between diaphragm and ant/post liver
where is the subhepatic recess
between inferior surface of liver and transverse colon
where is Morisons pouch
between liver and right kidney
significance of Morisons pouch
deepest part of the peritoneal cavity when supine
fluid collects here in bed ridden patients
name of the fibrous layer covering the liver
Glissons capsule
what are the 4 lobes of the liver
right
left
caudate
quadrate
which lobe of the liver is the largest
right
where is the caudate liver lobe
on the upper visceral surface
between IVC + ligamentum venosum
where is the quadrate liver lobe
lower visceral surface
between the gall bladder + ligmentum teres fossa
what stricture separates the caudate and quadrate liver lobes
porta hepatis
role of porta hepatis
transmits all the vv/aa/nn/ducts except the hepatic vv
shape of liver lobules
hexagonal
what central structure drains the liver lobules
central vein
what are the 3 structures at the periphery of the liver lobules (aka the ‘portal traid’)
arterioles branching from the hepatic aa
venules draining to the hepatic portal vv
bile ducts draining into the hepatic ducts
also lymphatic vessels + CNX fibres
where does 25% of the blood supply to the liver come from
hepatic aa proper
hepatic aa proper is a branch of
coeliac trunk
where does the remaining 75% of the blood supply to the liver come from
hepatic portal vv
venous drainage liver
hepatic vv –> IVC
inn liver
hepatic plexus
sympathetic component of the hepatic plexus
coeliac plexus
parasympathetic component of the hepatic plexus
CN X
inn Glissons capsule liver
lower intercostal nn
anterior liver LN drainage
hepatic LN –> coeliac LN –> cisterna chyli
posterior liver LN drainage
phrenic + post mediastinal LN –> R lymphatic + thoracic ducts
is the gallbladder intra or retroperitoneal
intraperitoneal
where is the gallbladder
in fossa between inferior aspects of the R and quadrate lobes of the liver
structures anterior + superior to the GB (2)
inferior border of the liver
anterior abdominal wall
structures posterior to the GB (2)
transverse colon
proximal duodenum
structures inferior to the GB (2)
biliary tree
remainder of duodenum
name of fold in the neck of the gallbladder + significance
Hartmans pouch
common place for gallstones to get lodged
what are the 3 parts of the gallbladder
fundus
body
neck
what structure is the neck of the gallbladder continuous with
cystic duct
which is the largest part of the gallbladder
the body
what structures is the body of the gallbladder adjacent to?
liver
transverse colon
superior duodenum
movement of bile to the hepatic ducts
bile secreted from hepatocytes
–> canaliculi
–> intralobular ducts
–> collecting ducts
–> hepatic ducts
what vessel does the hepatic duct run along side
hepatic vv
which 2 ducts join together to make the common bile duct
cystic duct + common hepatic duct
which 2 ducts join together to make the ampulla of vater
pancreatic duct + common bile duct
what regulates the ampulla of vater
sphincter of Oddi
via what does the bile empty into the duodenum from the Ampulla of vater
major duodenal papilla
aa supply gallbladder
cystic aa
cystic aa is a branch of
R hepatic aa
vv supply to the neck of the GB
cystic vv
cystic vein empties into
portal vein
vv drainage body/fundus of the GB
hepatic sinusoids
symp inn gall bladder
coeliac plexus
parasymp inn gall bladder
CNX
LN drainage gallbladder
cystic LN (at GB neck) –> hepatic LN –> coeliac LN
where is Calot’s traingle
at porta hepatis
superior border Calot’s triangle
inferior surface of the liver
medial border Calot’s triangle
common hepatic duct
inferior border Calot’s triangle
cystic duct
contents Callots triangle (4)
R hepatic aa
cystic aa
LN of Lund
lymphatics
what is the LN of Lund
1st lymph node of the gallbladder
importance of Calot’s triangle in lap chole’s
permits safe ligation of cystic aa + duct
and R hepatic aa ID’d
if not delineated - may have to do subtotal cholecystectomy or open cholecystectomy
what is mesentary
double fold of peritoneal tissue which suspends the SI + LI from the posterior abdominal wall
what is the mesentary root?
where the mesentary olbiquely attaches to the posterior abdominal wall
how many flexures of note along the mesentary?
6
what are the 6 flexures of note along the mesentary?
duodenojejunal, ileocaecal, hepatic, splenic, betw descending + sigmoid , sigmoid + rectum
mesentary of SI - mobile or flattened again posterior abdo wall
mobile
R mesocolon - mobile or flattened again posterior abdo wall
flattened
T mesocolon - mobile or flattened again posterior abdo wall
mobile
L mesocolon - mobile or flattened again posterior abdo wall
flattened
mesosigmoid - mobile or flattened again posterior abdo wall
medial portion flattened
rest mobile
mesorectum - role
anchors rectum through pelvis
what are the functions of mesentary? (2)
1 - anchor intestines in place whilst still allowing movement
2- conduit for vessels
what is Toldt’s fascia
additional connective tissue layer attaching the mesentary to the posterior abdominal wall
what does Toldt’s fascia contain
lymphatic channels
where do the superior mesenteric LN drain into
pre-aortic LN
what does the gubernaculum become in males?
small scrotal ligament
what does the gubernaculum become in females?
ovarian ligament
round ligament uterus
mid-inguinal point
1/2 way between PS +AS IS
significance of mid-inguinal point
femoral pulse can be palp’d here
midpoint inguinal ligament
1/2 between ASIS + PT
what is just above the midpoint of the inguinal ligament
opening to the inguinal canal
roof inguinal canal
transversalis fascia
IO
TA
floor inguinal canal
inguinal ligament
lacunar ligament
anterior border inguinal canal
aponeurosis external oblique
posterior border inguinal canal
transversalis fascia
what forms the deep ring of the inguinal canal
transversalis fascia
where is the superficial ring of the inguinal canal
just sup to the PT
what forms the superficial ring of the inguinal canal
invagination of EO + intercrural fibres
contents inguinal canal (3)
spermatic cord/round ligament
ilioinguinal nn
genital branch GF nn
which inguinal ring does the ilioinguinal nn NOT pass through
deep inguinal ring
which structure is most at risk during inguinal hernia repair
ilioinguinal nn
indirect inguinal hernia - medial or lateral to epigastric vessels
lateral
direct inguinal hernia - medial or lateral to epigastric vessels
medial
indirect vs direct hernia - which is more common
indirect
medial border inguinal triangle/Hasslebach’s
lateral border rectus abdominis
lateral border inguinal traingle/Hasslebachs
inferior epigastric vessels
inferior border inguinal triangle/Hasslebach’s
inguinal ligament
what are the inferior epigastric vessels a branch of
external iliac aa/vv
