embryology of the abdomen Flashcards
(148 cards)
1
Q
what does the diaphragm develop from
A
the septum transversum in the neck close to the thoracic inlet also contributed to from: pleuroperitoneal membranes dorsal mesentary of the oesophagus ingrowth from the body wall
2
Q
where do diaphragmatic muscles originate from
A
the xiphoid process
3
Q
where does the left crus arise from
A
L1 and 2
4
Q
where does the right crus originate from
A
L1,2 and 3
5
Q
where is the median arcuate ligament found
A
in the midline at t12
6
Q
describe the course of the right crus
A
fibres travel up and insert on the central tendon of the diaphragm
some cross the midline to form a loop around the oesophagus
7
Q
where is the bare area of the diaphragm
A
posterior to the liver
is it not covered by peritoneum
8
Q
what passes through the diaphragm at T8, through the central tendon
A
inferior vena cava
right phrenic nerve
9
Q
what passes out of the diaphragm at T10 through the right crus
A
left gastric artery from the coeliac artery
oesophagus, ant and post vagal trunks, left gastric vein
10
Q
what passes out of the diaphragm at T12 behind the median arcuate ligament
A
thoracic duct, azygous vein and hemiazygous vein
descending thoracic aorta
11
Q
what passes through the crura
A
greater and lesser splanchnic nerves
12
Q
what passes behind the median arcuate ligament
A
left and right sympathetic trunks
13
Q
what is the most common type of hiatus hernia
A
sliding - 90% of cases
14
Q
what happens in a sliding hernia
A
the intra abdominal part of the gastro-oesophageal junction rises above the oesophageal hiatus. This means some of the acid secreting parts of the stomach are above the diaphragm. leads to heart burn and dysphagia. may be asymptomatic
15
Q
what is a rolling hernia
A
the fundus herniates but the gastro oesophageal junction is intact. May cause dysphagia, early satiety or inability to hold down food.
16
Q
where are diarphragmatic hernias usually found
A
in neonates
presents with resp distress and cyanosis. Look for asymmetry on clinical examination
17
Q
what is the purpose of the peritoneum
A
allows movement and distension of the GI tract
18
Q
what is the difference in peritoneum between males and females
A
males- closed cavity
females- communication with the exterior through uterine tubes, the uterus and vagina
19
Q
what is the consequence of female peritoneal arrangement
A
possible spread of infection from exterior to interior of peritoneal cavity
20
Q
where is the extraperitoneal fascia
A
between the parietal peritoneum and the fascial lining of the abdominal wall (transversalis fascia)
it helps to support the kidneys
21
Q
where is the lesser peritoneal sack
A
lies behind the stomach and lesser omentum. extends slightly into the greater omentum
22
Q
what is the epiploic foramen (of Winslow)
A
allows communication between the greater and lesser sacs
23
Q
what structures does the peritoneum form
A
omenta
mesenteries
ligaments
24
Q
what is the greater omentum derived from
A
the dorsal mesentery
hangs from the greater curvature of the stomach and first part of the duodenum
overlies the transverse colon and small intestine
25
where is the lesser omentum
passes from the lesser curvature of the stomach and first part of duodenum to the inferior border of the liver
26
what is the hepatoduodenal ligament
the free edge of the lesser omentum containing the portal vein, hepatic artery and bile duct
27
what does epiploic mean
used to describe something associated with the omentum
28
what are mesenteries
double layered peritoneal folds that attach viscera to the posterior abdo wall
conduits for vessels, nerves and lymphatics
29
what are the different mesenteries
small intestine mesentery
transverse mesocolon
sigmoid mesocolon
30
what is the Mesentary
double layered fold of peritoneum that connects the jejunum and ileum to the posterior abdom wall
31
describe the course of the Mesentary
base starts left of L2 and passes obliquely downwards to the right, ending just above the sacro iliac joint,
it crosses the 3rd part of the duodenum, aorta and IVC, right gonadal vessels and right ureter
it contains branches of SMA and SMV, with nerves and lymphatics
32
describe the vasa recta of the jejunum
few arcades with long vasa recta to the intestine
33
describe the vasa recta of the ileum
many arcades with short vasa recta. This helps surgeons to identify it
34
what is the sigmoid mesocolon
the double layered fold of peritoneum that connects the sigmoid colon to the posterior abdom wall
35
where is the sigmoid mesocolon
root is in the left iliac fossa, crossing the birfurcation of the left common iliac vessels and the left ureter
it transmits the sigmoid branches of the inferior mesenteric vessels, plus nerves and lymphatics
36
what does the transverse mesocolon do
suspends the transverse colon from the posterior abdo wall
37
where is the transverse mesocolon
inferior to the pancreas
| carries branches of the middle colic vessels
38
how does the transverse mesocolon divide the peritoneal cavity greater sac
divides it into supra and infra colic compartments
39
what does the supra colic compartment contain
liver stomach and spleen and part of the duodenum
40
what does the infra colic compartment contain
jejunum, ileum, ascending colon and descending colon. part of the duodenum
41
what divides the infracolic compartment
the Mesentary divides it into right and left halves, each has a paracolic gutter
42
what is Morison's pouch also known as
right subphrenic recess or hepatorenal recess
43
where might pus collect and form abscesses when the patient is recumbent
Morison's pouch
44
what seperates the rectum from the uterus in females
rectouterine pouch
45
what seperates the rectum from the bladder in males
rectovesical pouch
46
what separates the bladder and uterus in females
vesico uterine pouch
47
what is a peritoneal fold
a reflection of peritoneum with more or less sharp borders
usually covers blood vessels, ducts and obliterated foetal vessels
it connects two organs together
48
what is the importance of the lesser sack
allows distension of the stomach after a meal
49
what is the hepatogastric ligament
passes from the lesser curvature of the stomach to the liver
50
where may peritoneal folds or recesses form
where the intestine moves from being retro to intraperitoneal e.g. a paraduodenal recess
possible site for hernia
51
what is the significance of the peritoneal pouches, recesses, spaces and gutters
can house puss or blood or allow the spread of infection around the abdomen
52
where is the right hepatorenal pouch
behind the liver
above the kidney
puss can get into the space and form and abscess
it could overflow into the lesser sack
this is more likely if the patient is recumbent
this is due to the proximity to the epiploic foramen
53
what folds are visible on the anterior abdominal wall peritoneum
lateral umbilical folds, medial umbilical folds and median umbilical fold
54
what does the median umbilical fold contain
urachus which extends from the urinary bladder to the umbilicus
55
what do the medial umbilical folds contain
obliterated umbilical arteries extending from the internal iliac arteries to the umbilicus
56
what raises the lateral umbilical folds
inferior epigastric arteries
| extending from the deep inguinal rings to the arcuate lines
57
what connects the liver to the diaphragm
falciform ligament, coronary ligament and the right and left triangular ligaments
58
what connects the spleen to the posterior abdominal wall and to the stomach
splenorenal and gastro splenic ligaments
| part of the greater omentum
59
what is the allantois
a canal that drains the urinary bladder of the foetus and runs with the umbilical cord
it becomes the urachus
60
what does intra peritoneal mean
the organ is almost totally covered with visceral peritoneum and is suspended within the peritoneal cavity
61
what does retroperitoneal mean
organs lie outside or behind the peritoneum and are only partially covered with visceral peritoneum
62
is the ovary intraperitoneal?
yes- it has absorbed its peritoneal covering
63
what does secondarily retroperitoneal mean
the mesentery has been resorbed and lost
| it used to be intra peritoneal but then moved out
64
what organs are 1o retroperitoneal
adrenal glands
kidneys
ureter
bladder
Aorta
IVC
oesophagus
rectum
65
what organs are 2o retroperitoneal
head, neck and body of the pancreas
the distal part of the duodenum
ascending and descending parts of the colon
66
where is the tail of the pancreas located
splenorenal ligament
67
where does appendix pain refer to
t10- peri umbilical
68
what is the parietal peritoneum sensitive to
pain, temperature, touch, and pressure
69
what is visceral peritoneum sensitive to
stretch and tear e.g. in inflammation
70
what is the parietal peritoneum in the pelvis supplied by
obturator nerve
| L2,3,4
71
what is the visceral peritoneum supplied by
autonomic afferent nerves that supply the viscera or travel in the mesentery
72
where does gallbladder pain refer to
shoulder tip and right side
73
what is a coelom
a cavity
74
what happens to the conceptus 12 days post fertilisation
implants in uterine mucosa
| forms bilaminar disc
75
what is the neural tube and body wall derived from
ectoderm
76
what is the cardiovascular, musculo skeletal system and coeloms derived from
mesoderm
77
what is the gastro-intestinal, respiratory and reproductive tracts derived from
endoderm
78
what does the notochord develop from
primitive node between endo and ectoderm
79
what is the peritoneal cavity derived from
intra embryonic coelom
80
what is the posterior abdo wall made from
mesoderm
81
what is exomphalos
failure of intestine to return to abdomen; lies within peritoneum and amnion, in umbilical cord
82
what is gastroschisis
failure of abdo wall, contents outside abdomen and not covered
83
what does the ventral mesenterary of the stomach and duodenum become
lesser omentum and falciform ligament
the falciform ligament and lesser omentum have free inferior borders
84
what is the foregut
the anterior part of the alimentary canal, from the mouth to the duodenum, just distal to the liver. The foregut develops from the folding primitive gut
85
what nerve supplies the foregut
coeliac trunk, refers pain to epigastrium T7-9
86
What does the foregut give rise to
oesophagus, respiratory diverticulum, stomach, proximal duodenum, liver, billary system, pancreas and spleen
87
what axes does the stomach rotate about
longitudinal axis and AP axis
88
when does the stomach appear
4th week of development as a dilation of the foregut
89
how does the stomach rotate
90 degrees clockwise around the longitudinal axis so that the left side faces anteriorly and the lesser curve faces to the right and greater to the left
AP axis so the pyloric part comes to lie on the right and oesophago-gastric junction slightly left so the greater curve faces left and inferior
90
how does the duodenum move during development
it is initially found in the midline but the rotations of the stomach cause it to rotate and swing on the right
it then falls onto the posterior abdominal wall and becomes retroperitoneal
91
describe the development of the duodenal lumen
proliferation of cells which destroys the lumen then it is re-canalised
92
when does the liver develop
3rd week
| from and endodermal bud
93
describe the development of the liver
it penetrates the ventral mesentery and septum transversum and gives rise to the hepatic ducts and gallbladder
the liver develops in the ventral mesentery and grows up to reach the septum transversum
94
what does the pancreas form from
dorsal and ventral endodermal buds from the duodenum, the rotation of the latter causes the ventral bud to migrate around to lie behind and fuse with the dorsal bud so that the adult pancreas lies in the curve of the duodenum
the ducts of the dorsal and ventral buds unite to form the main pancreatic duct
the accessory duct is a remnant of the duct of the dorsal bud
95
what does the visceral peritoneum of the liver develop from
the ventral mesentery directly in contact with the liver
96
what is an annular pancreas
the ventral pancreas may become bifid which then form an obstructive ring around the duodenum
a bifid gallbladder is also possible
97
what does the liver divide the ventral mesentery into
lesser omentum and falciform ligament
98
how does rotation of the stomach affect the ventral mesentery
throws it to the right
99
where is the umbilical vein
the free edge of the falciform ligament
100
where is the bile duct
the free edge of the lesser omentum along with the hepatic artery and portal vein
101
where is the spleen
dorsal mesentery
102
where is the free edge of the lesser omentum
vertically between the liver and duodenum
103
where is the lesser sac
posterior to the stomach and the lesser omentum
104
what is the anterior boundary of the epiploic foramen
free border of the lesser omentum with the bile duct, hepatic artery and portal vein
105
what is the posterior border of the epiploic foramen
IVC
106
what is the superior border of the epiploic foramen
caudate process of the caudate lobe of the liver
107
what is the inferior border of the epiploic foramen
first part of the duodenum
108
what is Pringle's manoevre
compress the hepatic artery and portal vein between the finger and thumb to control bleeding
109
what is the anterior border of the lesser sac
caudate lobe of liver, lesser omentum and stomach
110
what is the posterior border of the lesser sac
pancreas
111
what is the lateral border of the lesser sac
left kidney and adrenal gland, epiploic foramen
112
where is the lesser sac
extends upwards as far as the diaphragm and downwards a little way between the layers of the greater omentum
113
what is the dorsal mesentery
The portion of mesentery attached to the greater curvature of the stomach. it forms the greater omentum
114
what is the space within the greater omentum called
omental bursa which is the same as the lesser sac
115
where is the spleen
within the dorsal mesentery
116
What is the lienorenal ligament
double layers of peritoneum between the spleen and the posterior abdominal wall close to the kidney
117
what is the gastrolienal/ gastrosplenic ligament
the double layer between the spleen and the stomach
118
where is the tail of the pancreas
extends into the lienorenal ligament
119
where is the midgut
commences immediately distal to the entrance of the bile duct into the duodenum and ends 2/3rds along the transverse colon
120
what is the nerve supply of the midgut
superior mesenteric plexus- refers pain to the peri-umbilical region -T10
121
when does the midgut develop
week 5
122
what connects the midgut to the yolk sac
vitelline duct
123
through what angle does the midgut rotate
90 degrees anti clockwise in the hernia
a further 180 degrees as the loop drops back into the abdomen at 10 weeks
this leads to about 270 degrees rotation around the axis of the superior mesenteric artery
124
what does the cranial limb of the midgut form
jejenum and ileum
125
describe some congenital abnormalities related to the midgut
```
partial or abnormal rotation
Meckel's diverticulum
vitilline cyst
vitilline fistula or patent duct (faecal discharge at umbilicus)
failure of recanalization (narrowing or obstruction of the GI tract)
gastrochisis
Omphalocele
umbilical hernia
```
126
when is development of the hindgut
end of the 3rd week
127
what develops from the hindgut
distal transverse colon
descending colon
sigmoid colon
rectum and upper anal canal
128
what is the innervation of the hind gut
inferior mesenteric plexus
| refers pain to the suprapubic region -t12
129
what does the most inferior part of the hindgut develop from (anorectal canal)
cloaca
| also develops into the urogenital system
130
what is the distal third of the anal canal derived from
ectoderm
| marked by the pectinate line
131
what is the reason for imperforate anus
the anal membrane does not break down
132
what is the reason for urogenital - anal fistulae
common embryological origin
133
what types of anal-genital fistulae exist
uro-rectal fistulae
rectoperineal fistulae
rectovaginal fistulae
134
what is Hirchsprung disease
lack of normal colonic innervation leads to a constricted, aganglionic segment of bowel, with a distended segment proximally where the innervation is normal
135
describe the origins of the mesentery
base starts just left of L2 and passes obliquely downwards to the right ending above the sacroiliac joint
it crosses the 3rd part of the duodenum, aorta and IVC, right gonadal vessels and right ureter
136
describe the root of the sigmoid mesocolon
root is in the left iliac fossa, crossing the birfurcation of the left common iliac vesses and left ureter
it transmits the sigmoid branches of the inferior mesenteric vessels plus nerves and lymphatics
137
describe the root of the transverse mesocolon
fused to the inferior part of the greater omentum
root is inferior to the pancreas
transmits the middle colic vessels
138
what are the paracolic gutters
spaces between the colon and the abdominal wall
139
what is the innervation of the peritoneum lining the ant abdominal wall
lower six thoracic and first lumbar nerves
| t7-12 and L1
140
what is the nerve supply of the diaphragm
ventral rami of c3,4,5
141
what are the components of the diaphragm
septum transversum
pleuroperitoneal membranes
dorsal mesentery of the oesophagus,
ingrowth from the body wall
142
which part of the diaphragm contributes to the oesophageal hiatus
the right crus
143
where does the left gastric artery pass through the diaphragm
t10
144
where do the anterior and posterior vagal trunks pass into the abdomen
t10, through the right crus but left of the midline
145
where does the right phrenic nerve enter the abdomen
t8, through the central tendon
146
where does the descending thoracic aorta enter the abdomen
t12, behind the median arcuate ligament
147
what structures pass through the crura
greater, lesser and least splanchnic nerves
148
what do the dorsal and ventral endodermal buds go on to form
pancreas
