Clinical Correlations

Nerve root supply to Stomach

T6-T9

Nerve root supply to Small intestines

T8-T10

Nerve root supply to APPENDIX

T10

Nerve root supply to Ascending & Transverse colon

T10-T11

Nerve root supply to Proximal descending colon

T12-L1

Nerve root supply to Distal descending colon

L2-L3

Nerve root supply to Rectum

S2-S4

In colonic diverticulosis multiple false diverticulae develop along where

the large intestine

What are diverticulae

External evaginations or out-pocketings of the mucosa of the colon (Acquired mucosal herniations which protrude through weak areas of the muscular wall)

Where on the colon wall do diverticulae most commonly occur

on the mesenteric side of two bands of taenia coli (omental and free) due to the perforating nutrient arteries

On what section of the large intestines are diverticulae most common

Sigmoid colon

What age is most affected by Colonic Diverticulosis

middle-aged and beyond

Risk factors for Colonic Diverticulosis

Risk factors include: low fiber (high meat) diet, BMI>25

Problems that diverticulae can cause

Can become infected and rupture

gastrointestinal (GI) system has how many major venous systems - name them

2

Systemic venous system

Hepatic portal venous system

What does the Systemic venous system consist of

Veins that drain deoxygenated blood directly towards the heart

Why is the systemic venous system called the caval system

it involves the superior & inferior vena cavae

What does the Hepatic portal venous system consist of

Veins that drain nutrient rich deoxygenated blood from the intestines and the spleen directly towards the liver

In what way is blood supply to the liver unique

the liver is unique in that it receives both oxygenated and deoxygenated blood → from the proper hepatic artery and hepatic portal vein respectively

What is a portal system & 2 examples

Defined as a part of the circulation in which blood draining from the capillary bed of one structure flows through a larger vessel(s) to supply the capillary bed of another structure before returning to the heart

Examples include:

• Hypothalamus and pituitary gland

• Liver

What is Cirrhosis of the Liver

Progressive destruction of hepatocytes

Liver cells are replaced by fibrous (scar) tissue and regenerative nodules (lumps)

➢ Liver becomes firm

➢ Circulation becomes inhibited

Cirrhosis of the Liver treatment

Treatment may involve a shunt of venous blood from the portal system to the caval (systemic) system, or if the cirrhosis is very advanced then a liver transplant may be necessary

Portal hypertension can be a cause for many things. Make a list

Varices

Caput medusa

hemorroids

How does portal hypertension cause Varices, Caput medusa & hemorroids

Portacaval Anastomoses

What causes problems at Portacaval Anastomoses

The hepatic portal vein and its tributaries have no valves, therefore if the venous drainage of the gastrointestinal tract gets blocked at the hepatic portal vein, then blood can bypass the liver by flowing in a reverse direction and drain to the inferior vena cava through an alternative route, causing build up & other problems

Blockage of the left gastric vein results in backflow of blood to where, causing what

If there is a blockage in the left gastric vein, blood can flow back into the esophageal veins, leading to esophageal varices.

Blockage of the paraumbilical veins results in backflow of blood to where, causing what

if there is a blockage in the paraumbilical veins, blood can flow back into the epigastric veins, leading to caput medusae.

Blockage of the anorectal veins results in backflow of blood to where, causing what

If there is a blockage in the superior rectal vein, blood can flow back into the middle and inferior rectal veins, leading to hemorrhoids.

Eosophageal varices can occur at what anastomoses between the portal & caval venous systems

Anastomosis between:

Portal system – Left and right gastric veins

Caval system – Esophageal veins

Caput medusa can occur at what anastomoses between the portal & caval venous systems

Anastomosis between:

Portal system – Paraumbilical veins

Caval system – Epigastric veins

What causes Caput Medusa

If blood is unable to effectively flow through the liver, it can cause retroflow in the paraumbilical veins which now drain into the periumbilical veins

The superficial veins of the anterior abdominal wall (superficial epigastric and thoracoepigastric) then become extremely dilated and varicose which over time look like snakes slithering under the skin

Treatment for portal hypertension

divert the portal blood by creating a “shunt” or create communication between larger veins of the caval system in order to relieve pressure:

• Hepatic portal vein → Inferior vena cava

• Splenic vein → Left renal vein

Haemorrhoids can occur at what anastomoses between the portal & caval venous systems

Anastomosis between:

Portal system – Superior rectal veins

Caval system – Inferior rectal veins

Differences between internal & external hemorrhoids (location, pain level)

Internal hemorrhoids:

▪ Found above the pectinate line

▪ Will not be painful → visceral innervation

External hemorrhoids:

▪ Found below the pectinate line

▪ Would be extremely painful → somatic innervation!

If internal hemorrhoids were damaged, what would the result be

If damaged then would result in bright red blood in the stool as this is close to the source and the blood has not been digested → Lower GI tract bleed

How do external hemorrhoids develop

Develop from varicose perianal veins that are part of the caval system

Name the arteries involved in an anastomosis between the foregut & midgut

Superior pancreaticoduodenal artery

Inferior pancreaticoduodenal artery

Name the arteries involved in an anastomosis between the midgut & the hindgut

Middle colic artery

Left colic artery

What is The Marginal artery of Drummond

term that is used to describe the arteries supplying the midgut and hindgut when collectively they form a continuous circle along the inner border of the large colon

commonest area of colonic ischemia

splenic flexure

Why is the commonest area of colonic ischemia the splenic flexure

During development, the middle colic artery may not meet with the left colic artery

Significance of the anastomosis of the superior and inferior mesenteric arteries

provides COLLATERAL flow in the event of occlusion or significant stenosis

Peritonitis

Infection can occur if gas, fecal matter or bacteria enter the peritoneal cavity which would result in inflammation of the peritoneum

What is this procedure called

Paracentesis

Differentiate between pain felt from Inflammation of PARIETAL/VISCERAL peritoneum

Inflammation of PARIETAL peritoneum

• Sharp, well-localized pain

• Tenderness on palpation

Inflammation of VISCERAL peritoneum

-Generalized, referred pain that is felt in the associated dermatome of the organ

Excess fluid in the peritoneal cavity is called

Ascitic fluid (condition = ascites)

(can contribute to peritonitis)

A fluid rich in cellular elements, serum, fibrin, acid or pus that has seeped out and been discharged from an inflamed organ or vessel

Exudates

(can contribute to peritonitis)

What are Peritoneal adhesion

fibrous bands that form abnormal connections

Give 2 types of peritoneal adhesions

Visceral peritoneum attaching to an adjacent organ

Visceral peritoneum attaching to the parietal peritoneum

What causes peritoneal adhesions to form

Form as a result of damage to the peritoneal surface when sticky fibrin appears in order to assist with the healing process

Complications with peritoneal adhesions

Adhesions limit the normal movement of viscera and could lead to complications:

➢ Intestinal obstruction (a.k.a. volvulus)

➢ Chronic pain

Treatment for peritoneal adhesions

Laparotomy: Surgical incision into abdominal cavity prior to major surgery

Adhesiotomy: Surgical separation of adhesions Peritoneal Adhesions

2 surgical techniques for an appendectomy

1. Through a transverse or grid-iron (muscle-splitting) incision centered at McBurney’s point. 2. Through laparoscopic surgery

both appendectomy surgical techniques involve the correct ligation of what artery

appendicular artery

What nerves are most at risk in the transverse / grid-iron incision at mcBurney’s point

Nerves most at high risk of damage during this surgery due to travelling through the anterior abdominal wall musculature:

• Iliohypogastric nerve (L1)

• Ilioinguinal nerve (L1)

How does the pain differ in initial vs acute appendicitis

Initial appendicitis: General VISCERAL Afferent (GVA) pain fibers are referred to T10 dermatome

Acute appendicitis: General SOMATIC Afferent (GSA) pain fibers are localized at McBurney’s Point

most commonly injured abdominal organ

spleen

How is the spleen the most commonly injured abdominal organ

Despite being protected by the rib cage, a traumatic blow to the left side may fracture the ribs and result in fragments of bone lacerating the spleen

Example could be becoming impaled against the steering wheel during a road traffic accident

If the spleen ruptures, this will lead to

Shock

Intraperitoneal hemorrhage – profuse internal bleeding

Splenectomy

Surgical removal of the spleen to prevent bleeding to death

Splenomegaly

Pathological enlargement of the spleen (up to 10x normal size) accompanied by high blood pressure

Cholelithiasis

Gallstones

small lumps of solid stone-like deposits which form in the gallbladder

Cholelithiasis risk factors

Crystals form when there are high concentrations of cholesterol and can be associated with individuals who are regularly dehydrated

Relatively common in females

Cholelithiasis symptoms

Pain in the right upper quadrant (RUQ)

Pain may be referred to the right neck/shoulder region

Nausea

Cholecystitis → Inflammation of the gallbladder

Jaundice

What is a common constriction site where cholelithiasis often become painfully lodged

hepatopancreatic ampulla

What components make up gall stones

Cholesterol

Calcium

Phosphate

Bilirubin

Triglyceride

Bile acid

Match

1. hepatolithiasis

2. cholecystolithiasis

3. choledocholithiasis

a Gall bladder stones

b Extrahepatic bile duct stones

c Intrahepatic bile duct stones

1c

2a

3b

Describe content of Intrahepatic bile duct stones (hepatolithiasis)(cholesterol/pigment)

Brown pigment & cholesterol stones

Describe content of extrahepatic bile duct stones (choledocholithiasis)(cholesterol/pigment)

Primary stones = brown pigment

Secondary stones = cholesterol

Describe content of Gall bladder stones (cholecystolithiasis)(cholesterol/pigment)

Cholesterol (or black pigment) stones

Cholecystectomy

surgical procedure to remove the gallbladder

Gall stones can cause severe what

biliary colic (pain in the RUQ)

Important surgical danger area in a Cholecystectomy

Important to identify the the cystohepatic triangle to determine if there is a variation the cystic artery or biliary apparatus

What is done in the cystohepatic triangle to prevent bleeding & release of bile

Once identified, the cystic duct and cystic artery are ligated and divided to prevent bleeding and the release of bile

Cystohepatic Triangle / Triangle of Calot borders

Superior border: Inferior border of the Liver

Medial border: Common hepatic duct

Lateral border: Cystic duct

What is regarded as the key component to performing a safe laparoscopic cholecystectomy

Dissection of the cystohepatic triangle

most common type of pancreatic cancer

Cancer of the head of the pancreas

A tumour in the head of the pancreas could obstruct what

Common bile duct

Hepatopancreatic ampulla

A tumour in the neck/body of the pancreas could obstruct what

Hepatic portal vein

Inferior vena cava

Retention of bile pigments (like in pancreatic cancer) will lead to what

jaundice

What is jaundice

Yellowing of the skin and sclera of the eyes usually results if bile is unable to be released into the duodenum

Jaundice can lead to what change in faeces

can lead to stools/faeces becoming acholic

Another name for a whipple procedure & its use

Conventional pancreaticoduodenectomy

surgical treatment for tumours and other diseases of the pancreatic head, duodenum, bile duct, or periampullary region. It involves the removal of:

• The head of the pancreas

• The duodenum (first part of the small intestine)

• The gallbladder

• Part of the common bile duct

• Sometimes part of the stomach (pylorus-preserving variant spares it)

After removing these structures, the surgeon reconstructs the digestive tract to allow for the continued flow of bile and pancreatic enzymes.

Pyrosis

Heartburn

Pyrosis is the most common type of esophageal discomfort and substernal pain - what does it involve

Typically a result of regurgitation of gastric acid into the abdominal part of the esophagus

What is pyrosis a symptom of (2)

Gastro Esophageal Reflux Disorder (GERD)

Hiatal Hernia

What has the job of preventing acid reflux

inferior esophageal sphincter

2 most common stomach diseases

Gastric ulcers and gastritis

What is a peptic ulcer

A distinct lesion (or necrosis) of the mucosa in either the stomach, pyloric canal or duodenum as a result of acid erosion

Peptic Ulcers symptoms

Haematesmesis: vomiting “coffee ground” blood

Melena: black, foul-smelling faeces

Problem associated with peptic ulcer on lesser curvature of the stomach

Erode GASTRIC artery

Problem associated with peptic ulcer on the anterior wall of the stomach

Erode the LIVER and cause peritonitis

Problem associated with peptic ulcer on the posterior wall of the stomach

Erode SPLENIC a. & the PANCREAS

Majority of gastric cancers are what

adenocarcinomas

Why is surgery on carcinoma of the stomach difficult

Surgery is difficult due to the inability to remove all of the lymphatic nodes associated with the stomach

can help identify small gastric tumors

Transillumination

What is a sign that carcinoma of the stomach is advanced

if Virchow’s lymph nodes (left supraclavicular) are palpable, the malignancy is advanced and prognosis is poor

Troisier’s Sign

Hard, palpable, enlarged LEFT supraclavicular lymph nodes indicate metastatic cancer in the abdomen

Name 2 types of Inflammatory Bowel Disease (IBD)

Crohn’s Disease & Colitis

Difference between Crohn’s Disease & Colitis

Crohn’s disease has very similar symptoms as ulcerative colitis, however, colitis is limited to the colon