1.2 Anatomy of the Abdomen Flashcards
List the 3 sections of the oesophagus and potential constrictions at each
- Cervical: constriction can be caused by cricopharyngeus muscle
- Thoracic portion (bulk): constriction can be caused by bronchi-aortic arch
- Abdominal portion: constriction caused by oesophageal hiatus of diaphragm (T10)
What ligament allows for movement of the oesophagus whilst keeping it tethered as it enters the thorax?
Phreno-oesophageal ligament
Describe the 2 types of oesophageal hernias
1. Sliding hiatal hernia: failure of the phreno-esophageal ligament to keep the stomach in place (commonly aquired). Often due to a displaced LES
- Symptoms: pyrosis (“heartburn”) and dysphagia
2. Rolling (paraesophageal) hernia: fundus of stomach protrudes through the diaphragm to form a pouch (less commonly aquired)
- Symptoms: diffuse pain
- Medical Emergency!
Which type of esophageal hernia is a medical emergency and why?
Rolling: because the fundus of the stomach can become necrotic due to the tight constriction
What are the pathways of venous drainage for the oesophagus?
- Most drain through systemic veins:
esophageal v ➞ azygous v ➞ SVC
- Veins lower down drain through the portal system:
esophageal v ➞ L gastric v ➞ portal v ➞ liver ➞ hepatic v ➞ IVC
What is a varix?
An enlarged and tortuous vein, unnaturally swollen
What is the primary cause of oesophageal varicies and why?
Portal hypertension
The oesophagus has porto-systemic anastomoses ➞ veins of portal circulation (draining to liver) and veins of systemic circulation (draining to heart) meet to drain the same structures
If there is hepatic fibrosis (e.g cirrhosis), scar tissue replaces normal tissue, blocking the flow of blood exiting via the hepatic vein. This causes portal hypertension.
As the veins draining the portal system do NOT have valves, this results in back pressure into the systemic circulation, seen as a varicies
List 3 signs that may be seen on examination of a patient with portal hypertension
Oesophageal varices
Rectal varices (haemorrhoids)
Caput medusae
Name 5 factors which may cause hepatocyte damage
- Alcohol
- Hep B, C, D
- Excess iron in the liver
- Autoimmune liver disease
- Obesity
Name two other locations besides the esophagus where portal-systemic anastomoses exist.
Incl the signs seen on examination for each
- The rectum: rectal varicies ➞ hemorrhoids
- The umbilicus: if blood can’t drain into the liver, more drains through the systemic circulation into the abdomen ➞ caput medusae
What is the ‘streamline flow of the Portal vein theory’?
How does this help predict the origin of a tumour based on it’s location in the liver?
Theory states that blood from the SMV and IMV mix incompletely in the PV, resulting in disproportionate distribution within the liver lobes.
The SMV distributes mainly to the right lobe compared to the IMV, which supplies both hemilivers similarly.
Therefore we can predict that tumours on the R lobe of the liver came through the SMV and originated from a midgut structure.
What other vein does the superior mesenteric vein combine with to form the portal vein?
Splenic vein
Into which regions does the spleen tend to enlarge in splenomegaly?
From the Left hypochondrium towards the R iliac fossa (downwards and medial)
Why is splenic rupture so dangeorus?
The spleen is highly vascularised and hence a rupture will lead to large blood loss
Pancreatic Cancer often invades the _______ of the pancreas. Invasion can compress and obstruct the _______ and/or _______.
If cancer invades posteriorly, it can invade/block portal venous confluence of ______ and ______.
head, bile duct, ampulla of vater, splenic, SMV
What can occur due to blockage of the common bile duct (ie. cancer in the pancreatic head)
Name 3 associated symptoms which may be seen
Blockage of the CBD and/or ampulla of vater can lead to erosion of bile pigment into the liver and boodstream.
Symptoms: jaundice, pale stools, dark urine (excessive bile being excreted
The small Intestine is the longest part of the GI tract and extends from the ______ region of stomach to the ______ junction
It consists of the _______, _______, _______
pyloric, ileocecal, duodenum, Jejunum, Ileum
The duodenum is C-shaped and located adjacent to the _________. It is connected to the liver by the _______ and can be divided in _____ parts.
head of the pancreas, hepatoduodenal ligament, 4
What connects the duodenum to the liver?
The Hepatoduodenal ligament
What are the 4 parts of the duodenum shown on the image below
Which region of the duodenum are duodenal ulcers most likely to occur
The Superior part ➞ “Duodenal cap”
Which section of the duodenum are the major and minor duodenal papillas located? What is the function of these
The descending part
papillas are where the biliary and pancreatic juices enter the dunodenum
Which part of the duodenum do the SMA and SMV cross anteriorly?
The inferior part
What is the suspensory ligament of Treitz and where is it located?
Ligament attaching the 4th part of the duodenum to the diaphragm above
Located in the ascending part of the duodenum
Give 2 potential consequences of an aneurysm of the SMA and explain each
1) Entrapment of the L. renal vein (drains the L. gonad) between the AA and SMA. Results in a back-pressure tracing to the testis ➞ scrotal varicosities ➞ variocoele
2) Obstruction the duodenum, may be treated by ligation of the ligament of treitz
Intussusception is when the ______ portion of the intestine telescopes INTO a ______ segment of the intestinal tube.
It commonly involves the ______ and the ______ colon at the ______ junction.
proximal, distal, ileum, proximal, ileocolic
Label the image of the large intestine
Name 3 symptoms/consequences of intussusception
1) abdominal cramping
2) currant jelly stools ➞ dark red and mucoid
3) bowel perforation due to necrosis ➞ blood supply from SMA (ileocolic branches)
What is diverticulosis, whic part of the intestine is it most common in and which age group is most suseptible?
Multiple false out-pocketings of mucosa of colon, common occurs in the sigmoid colon and affects middle aged/elderly people → if inflammation occurs can lead to diverticulitis
The large Intestine recieves blood supply from distal ____ and _____
The procedure __________ can be used to visualize polyps and perform minor procedures such as biopsies.
MOST tumours of the colon occur in the ______ colon and the _______.
SMA, IMA, Colonoscopy, Sigmoid, Rectum
What is the significance of the ‘apple core sign’ on an X-ray?
Associated with constriction of the lumen of the colon by a stenosing annular colorectal carcinoma
What additional role does the Liver play in a Foetus
Haematopoiesis
What is the dual blood supply of the liver
1) Proper Hepatic artery (25%)
2) Portal Vein (75%)
What is the purpose of tethering of mesenteries?
Tethering of the mesenteries (incl the transverse mesocolon) limits some movement of fluid
BUT… sometimes fluid exudates can travel in paracolic gutters and track down to the pelvic cavity or sub phrenic spaces where abcesses may form
