Hindgut - Anatomy Flashcards
What supplies the blood to the hindgut?
IMA
Is the abdominal aorta intra or retroperitoneal?
Retroperitoneal (lying on posterior wall)
What does the right colic artery supply?
Ascending colon and hepatic flexure
What does the middle colic artery supply?
Some of hepatic flexure, proximal 2/3 of transverse colon
Where is the SMV? Where does it always sit?
Always to the right of the SMA (and by right I mean left when looking at it)
What is the function of the SMV?
Drains structures of the midgut
What is the ascending part of the duodenum held in place by?
Small peritoneal ligament –> ligament of treitz
Where does the SMA and SMV emerge?
Around L1, deep to neck of pancreas (trans-pyloric plane)
What is the falciform ligament a remnant of?
Ventral mesentery
What is the remnant of the umbilical vein?
Round ligament of the liver
Where does the oesophagus pass through the diaphragm?
T10
Where does the thoracic aorta pass through the diaphragm?
T12
Where does the vena cava pas through the diaphragm?
T8
What is found at the inferior aspect of the falciform ligament?
Thickened structure –> ligamentum teres
As the falciform ligament progresses towards the diaphragm, what does it split into?
Right and left coronary segments which leave liver and attach to inferior surface of diaphragm
Peritoneum also reflects off the posterior surface
If you slide your hand just inferior to the diaphragm in the sub-phrenic recess, why can your hand not go all the way around the liver?
Due to coronary ligaments reflecting off liver and attaching to diaphragm
What are the 4 anatomical lobes of the liver? What do you need to look at to appreciate these lobes?
Look at the visceral surface:
- Right lobe
- Left lobe
- Caudate lobe
- Quadrate lobe
Where do structures enter and leave the liver?
Porta hepatis
What is it called when the peritoneum reflects off the liver on the posterior surface and attaches to the diaphragm?
Posterior coronary ligament
At the lateral edge, the posterior and anterior coronary ligaments merge. Where do they merge?
Right and left triangular ligaments
What is the bare area of the liver?
As the peritoneum comes off the liver, there is a region of the liver that is devoid of visceral peritoneum (duller and more roughened)
How many segments can the liver be split into?
8
What does each segment of the liver recieve?
Its own arterial blood supply, own venous supply, own duct system for secreting bile (biliary system)
What does the hepatic vein drain into?
IVC
Where is the portal triad contained?
Free edge of lesser omentum (hepatoduodenal ligament)
What structures are found within the portal triad?
- Hepatic artery proper
- Common bile duct
- Portal vein
What forms the common bile around?
From the gall bladder, the cystic duct (bottom) meets the hepatic duct (top) to form the common bile duct
Where does the cystic artery come from?
Right hepatic artery
What does the cystic artery?
Gall bladder
What is the hepatoportal vein a combination of?
Majority of the veins coming from the GI tract –> splenic vein, IMV, SMV
Where is the splenic artery found?
Superior aspect of pancreas
Where is the splenic vein found?
Inferior aspect of pancreas
Where does the IMV drain into?
Drains hindgut into splenic vein
What is the hepatoportal vein formed by?
IMV, SMV, splenic (IMV drains hindgut, meeting splenic vein that then meets with SMV)
What also drains into hepatoportal vein (small contribution)?
Short gastric vein
Are the inferior mesenteric vessels intra or retroperitoneal?
Retroperitoneal
What are the branches of the IMA?
- Left colic
- Sigmoidal
- Superior rectal
What is the anastomotic loops between IMA and SMA?
Marginal artery
What does the middle colic join with to form marginal artery?
Some branches of the left colic
What is importance of marginal artery in times of decreased blood supply in IMA (e.g. during aneurysm)?
Can still provide hindgut with arterial blood via marginal artery which receives blood from SMA
What does the left colic artery supply?
The descending colon and splenic flexure
What vertebral level does the sigmoid colon meet the rectum? What is this junction called?
S3
Rectosigmoid junction
What is a portosystemic anastomosis?
Collateral communication between portal and systemic venous system
What is cause of varices?
An increase in blood within vein (hypertension) causes them to become swollen or enlarged
What can portal hypertension lead to?
Blood that usually courses to liver (portal system) now courses to IVC (systemic system) causing an enlargement of these vessels
How can portal hypertension affect the ligamentum teres?
Can cause it to reopen
What is the ligamentum teres?
Remnant of umbilical vein –> round ligament of the liver (thickened structure at posterior aspect of falciform ligament)
