Abdo Anatomy From Deb B

Front 1

what's the diff between the alimentary tract and the GI tract?

Back 1

Alimentary = the whole tube from mouth to anus
GIT = just stomach and intestines

Front 2

What structures are in the a) foregut, b) midgut and c) hindgut?

Back 2

Foregut --> oes, stomach + proximal duo (up to where the bile duct opens). Also, liver, gallbladder, spleen and most of pancreas
Mid --> duo (from the bile duct opening) to the Tv colon. Also the rest of the pancreas
Hind --> distal 1/3 of the transverse colon to upper half of anal canal

Front 3

What's the pectinate line?

Back 3

demarcation (in anal canal) between true gut (ie derived from mucous) + the skin derived part

Front 4

At what vertebral levels do the coeliac trunk, SMA and IMA come off the aorta?

Back 4

Coeliac -> T12
SMA -> L1
IMA -> L3

Front 5

What are the three branches of the coeliac trunk? And what do they each supply?

Back 5

Left gastric = small branch. Supplies stomach and some of oes.
Splenic = large - goes behind the stomach to the spleen
Common hepatic - also large

Front 6

What are the three branches of the IMA?

Back 6

Left colic artery
Sigmoidal artery
Superior rectal a - it's actually a continuation of the IMA (IMA becomes sup rectal at the pelvic brim)

Front 7

What is the marginal artery of Drummond?

Back 7

It's an anastomotic connection between the colic arteries (extends from beginning to end of teh colon)

Front 8

What two veins join to form the portal vein?

Back 8

The splenic vein and the SMV

Front 9

Where does the IMV join?

Back 9

It usually joins to the splenic vein (then the splenic vein joins with the SMV to form portal vein) But this is quite variable: IMV can also join at the junction of the splenic v and SMV or it can join directly onto the SMV itself (remember pic with the two blue dotted arrows showing alternate joining sites)

Front 10

Describe venous drainage for fore, mid and hind guts

Back 10

Foregut -> splenic
Midgut -> SMV
Hindgut -> IMV

Front 11

Where are the four sites of porto-caval anastomosis? What's the clinical sign'ce of these?

Back 11

1. Wall of the lower oesophagus
2. Wall of the rectum and anal canal
3. At the umbilicus (ie on anterior abdo wall)
4. Retroperitoneal
Clinical sign'ce: if you get portal venous hypertension, blood from portal circulation flows via these anastomoses -> can get varices at these four locations

Front 12

What happens with venous portal hypertension at the 4 sites of porto-caval anastomosis?

Back 12

Wall of lower oes -> get oes varices, haematemesis, bleeding into stomach + malaena
Wall of rectum + anal canal -> get haemorrhoids and bleeding into anal canal
Umbilicus (on ant abdo wall) -> get large visible veins radiating from the umbilicus. This is called caput medusae
Retroperitoneal anastomoses -> don't get observable effects here

Front 13

Describe the direction of lymphatic drainage from the gut

Back 13

1. Nodes on or close to gut wall
2. Nodes in mesentery and mesocolon
3. Pre-aortic LNs (these are the three gps for the diff gut parts: coeliac, SM and IM nodes)
4. Cysterna chyli = sac like structure at the lower end of the thoracic duct
5. Thoracic duct -> will return fluid into the venous system at the junction of teh left subclavian v and internal jug vein

Front 14

What are lacteals?

Back 14

They're lymph vessels in the small intestine. They absorb fat
-> lymph in the thoracic duct is milky after a fat meal

Front 15

What does parasymp innervation of the gut do? And symp innervation?

Back 15

PARA -> Increase peristalsis, opening of sm muscle sphincters + glandular secretion

SYMP -> opposite effect. Also vasoconstriction of the BVs

Front 16

Describe the para and symp innervation of the fore, mid and hind guts

Back 16

Fore and mid:
Para = vagus. Symp = T5-12 thoracic splanchnics

Hind:
Para = S2-4 pelvic splanchnics. Symp = L1-2 lumbar splanchnics

Front 17

How does visceral pain from the gut travel to the spinal cord?

Back 17

Along symp fibres to T and L spinal leves

Front 18

Where does gut pain refer to? (Fore, mid and hind)

Back 18

Foregut -> epigastrium
Mid -> umbilicus
Hind -> hypogastrium

Front 19

Describe the arterial supply, venous drainage and lymphatic drainage of the foregut

Back 19

Coeliac trunk
Splenic vein
Coeliac nodes

Front 20

Describe the arterial supply, venous drainage and lymphatic drainage of the midgut

Back 20

SMA
SMV
SM nodes

Front 21

Describe the arterial supply, venous drainage and lymphatic drainage of the hindgut

Back 21

IMA
IMV
IM nodes

Front 22

Describe the para and symp (+ganglia!) innervation of the foregut

Back 22

Para = vagus
Symp = thoracic splanchnics via coeliac ganglion

Front 23

Describe the para and symp innervation of the midgut

Back 23

Para = vagus
Symp = thoracic splanchnics via superior mes ganglion

Front 24

Describe the para and symp innervation of the hindgut

Back 24

Para = S2-4 pelvic splanchnics via inf mes ganglion
Symp = lumbar splanchnics via inf mes ganglion

Front 25

What is the vitelline duct?

Back 25

Communication between the future ileum (midgut) and the yolk sac

Front 26

Which part of the developing gut has a ventral mesentery? What viscera develop in here?

Back 26

only the foregut has ventral mesentery
Liver, gall bladder + ventral pancreatic bud develop here

Front 27

Which part of the gut has a physiological hernia during development? What happens when this part of the gut comes back?

Back 27

The midgut. Elongates and herniates into the umbilical cord
When it comes back into the abdo cavity, it rotates 270 degrees counter clockwise (axis of rotation = SMA)

Front 28

How does the stomach rotate during development? -> what does the early left side of the stomach become then?
Whats the clinical sign'ce of this?

Back 28

It rotates 90 degrees
-> left side of the stomach will become the anterior surface
Sign'ce: this is why the left vagal fibres mainly supply the anterior surface of stomach
Also, the rotation creates a peritoneal outpouching behind the stomach = the lesser sac / omental bursa

Front 29

What happens to the caecum during development? IE where does it start adn then finish?

Back 29

Caecum is at first high and midline
Then it moves down and to the right - ends up in the right iliac fossa

Front 30

How does a structure become secondarily retroperitoneal?

Back 30

Viscera moves to the side -> the dorsal mesentery fuses with the posterior abdo wall -> doesn't have a dorsal mesentery any more. It's fixed in position. The BVs become retroperitoneal as well

Front 31

What structures become secondarily retroperitoneal during development?

Back 31

Duodenum (except the first few cms), ascending colon + descending colon

Front 32

What structures retain a mesentery / mesocolon?

Back 32

Jejunum, ileum, transverse colon, sigmoid colon
Ie they're intra peritoneal -> free to move

Front 33

What's adherent to the back of the greater omentum? (ie what will you see if you lift it up)

Back 33

Transverse colon is adherent to the back of the greater omentum. Then below is the transverse mesocolon

Front 34

What's the difference between the abdominopelvic cavity and the peritoneal cavity?

Back 34

Abdominopelvic = bounded by muscles and bones
Peritoneal - within the abdominopelvic cavity - bounded by peritoneum

Front 35

What does the mesentery suspend?

Back 35

Jejunum and ileum

Front 36

What is a peritoneal ligament?

Back 36

Double or single layer of peritoneum that passes to an organ (eg falciform ligament: going from the liver to the diaphragm and ant abdo wall)

Front 37

What is a peritoneal fold?

Back 37

Fold of peritoneum that's raised from a body wall by an underlying vessel, duct or ligament

Front 38

What is the omental / epiploic foramen of winslow?

Back 38

Opening between the greater and lesser sacs of the peritoneal cavity

Front 39

Where does the lesser sac of teh peritoneum lie?

Back 39

It's posterior to the stomach and lesser omentum -> helps the stomach slip and slide as needed

Front 40

Why is the greater om referred to as the policeman of the abdomen?

Back 40

- Adheres to gastro-int defects -> limiting the spread of infxn
- Angiogenic activity -> enhances healing
- Milky spots within the greater om - contains macros, B and T cells -> absorbs and clears bac and other foreign material from the peritoneal cavity. Also supplies lymphocytes to the peritoneal cav when required

Front 41

What are the boundaries of the epiploic foramen?

Back 41

Hepatoduodenal ligament (free edge of the lesser om)
Duo
Liver
IVC