Lecture 11: Peritoneum and Abdominal Organs Flashcards
Upper and lower boundaries of the abdominopelvic cavity
Cranially: Diaphragm
Caudally: Levator ani and coccygeus muscles
2 divisions of abdominal cavity
- Abdominal cavity proper
- Pelvic cavity
Contents of abdominal cavity
Blood vessels, viscera, nerves, and peritoneum
Where does the abdominal cavity extend and why?
Into the rib cage to protect abdominal organs (especially forget organs)
Purpose of the greater (or false) pelvis
Protect lower abdominal organs
What part of the abdominal wall contains criss-crossing muscles and what are their functions
Anterior and lateral abdominal walls. Provides protection to this region, which contains soft and vital viscera.
What are the names of the 2 horizontal planes of the abdomen and their locations
Subcostal plane- costal cartilage of 10th rib
Transtubecular plane- iliac tubercles of iliac crest
What are the names of the vertical planes of the abdomen and their location
Midclavicular planes- From mid clavicle to between the anterior superior iliac spine and pubic symphysis
What are the six different regions of the abdomen in order (right to left)
Right hypochondriac, epigastric, left hypochondriac, right lumbar, umbilical, left lumbar, right inguinal, hypogastric, and left inguinal
What’s found in the right hypochondriac region?
Liver
What is found in the epigastric region?
Stomach
What is found in the left hypochondriac region?
Spleen
What is found in the right lumbar region
Right kidney
What is found in the umbilical region
Transverse colon
What is found in the Left lumbar region
Left kidney
What is found in the right inguinal region
appendix
What is found in the hypogastric region
Small intestine
What is found in the left inguinal region
Sigmoid colon
What are the 2 planes that divide the abdomen into four quadrants used by physicians
Median plane and transumbilical
What are the names of the 4 quadrants of the abdomen when divided by the median and transumbilical planes?
Upper left/right and Lower left/right quadrants
What was the embryonic precursor of the peritoneal cavity?
The intraembryonic coelomic cavity
What organs are contained within the peritoneal cavity
none
Are abdominal and peritoneal cavity synonymous?
No
Peritoneum
Serous membrane (thin layer of CT) covered by simple squamous epithelium (also called mesothelium)
What are the 2 peritoneum that delineated the peritoneal cavity
Parietal and visceral peritoneum
Which peritoneum is under extraperitoneal fat and transversals fascia that lies the abdominal wall?
Parietal peritoneum
Which peritoneum forms a shiny external covering over the abdominal organs
Visceral peritoneum
Mesentery definition
Double layer of peritoneum that encloses an organ and connects it to the body wall.
How do organs that are held within mesenteries receive blood?
Blood vessels travel through the mesentery to reach the organ
Peritoneal ligament definition
Double layer of peritoneum connecting an organ to the body wall or to another organ
Retroperitoneal definition
Organ that only slightly protrudes the peritoneal cavity
What doe retroperitoneal organs lack?
Mesenteries
Unique characteristics of retroperitoneal organs?
immobile and tough to access surgically
Primarily retroperitoneal
Never had a mesentery and never will (not gut organs)
Example of primarily retroperitoneal organ
Kidney
Secondarily retroperitoneal
They developed a mesentery but it was reabsorbed
Examples of secondary retroperitoneal organs
pancreas, duodenum, ascending and descending colon
How did the pancreas and duodenum loose their mesentery
Growth of the liver forces these two organs against the posterior back wall
How did the ascending and descending colons loose their mesentary
gut rotation cement rated the two structures against the posterior back wall
Location of subphrenic recess
Between the liver and thoracic wall
What boundaries from the hepatorenal recess
Bounded by the right kidney, liver, colon, and duodenum
What is the lowest point of the peritoneal cavity when the patient is laying down
The hepatorenal recess
In what recess does the vermiform appendix lie?
the retrocecal recess
What are the 2 divisions of the peritoneal cavity
The greater and lesser sac (or peritoneal cavity proper and omental bursa)
Location of the lesser sac
between the stomach and posterior body wall
What does the lesser sac allow for?
Dissension of the stomach
How does the lesser sac communicate with the greater sac?
Through the epiploic foramen of Winslow
What is another name for the epiploic foramen of Winslow?
Omental foramen
What are the lateral boundaries of the mental bursa
Glastrosplenic ligament and lienorenal ligament
What are the structures that are anterior and posterior to the omental bursa
Anterior: Stomach
Posterior: Pancreas
What are the 3 parts of the omental bursa
- Superior recess- between the liver and diaphragm
- Main portion behind the stomach
- Inferior recess- Between the double layers of the gastrocolic ligament
What recess is obliterated in the omental bursa during adulthood
the inferior recess
What forms the median umbilical fold
Formed by urachus
What is the urachus an embryonic remanent of
allantois
Function of the allantois
Connect the urinary bladder to anterior body wall
What is the medial umbilical fold a remanent of?
Umbilical arteries
What artery travels through the lateral umbilical fold?
The inferior epigastric artery
Where does the falciform ligament extend
From the umbilicus to liver
What does the falciform ligament contain
The ligamentum teres hepatic
What is the ligamentum teres hepatis a remanent of?
Umbilical v.
Which mesentery is the derivative of the falciform ligament
Ventral mesentery
What are the functions of the mesenteries that attach structures to the posterior body wall?
transport vessels, nerves, and lymphatics, and allow for mobility of intestines
What are the 3 mesenteries that suspend the intestines to the back wall
- Mesentery proper (suspends the jejunum and ileum)
- Transverse mesocolon (transverse colon)
- Sigmoid mesocolon (sigmoid colon)
Function of Greater Omentum
Attach the stomach and proximal duodenum to body wall
What did omentum derive from
primitive mesentery
Greater omentum location and description
Fat-filled apron suspended from the greater curvature of the stomach over intestines
Structural derivative of the greater omentum
Dorsal mesentery
How many layers was the greater omentum in the embryo
4 layers
How many layers is the greater omentum in the adult
2 layers
Why is the greater omentum the “policeman of the GI tract”
Localizes infection
What ligaments make up the major and minor portions of the greater omentum
Major- Gastrocolic ligament
Minor- Gastrosplenic and gastrophrenic ligaments
Role of the lesser omentum
Suspends the stomach (from lesser curvature) from the liver
What is the structural derivative of the lesser omentum
The ventral mesentery
What ligament from the liver attaches to the stomach in the lesser momentum
Hepatogastric ligament
What are the two ligaments that make up the lesser omentum
hepatogastric and hepatoduodenum ligaments
What are the four depressions (or pathways) for the conduction of fluid and infections formed by the attachments of mesenteries of the small intestine, ascending and descending colon
- Right paracolic gutter
- Gutter to the right of the mesentery
- Gutter to the left of the mesentery
- Left paracolic gutter
How is the right paracolic gutter formed
Formed from the fact that ascending colon is secondary retroparitoneal pushed against back wall and there is parietal paritoneum on the outside making an unimpeded path for fluid to travel when you are upright.
What is the role of the right paracolic gutter
Communication between hepatorenal recess and pelvis
What is the direction of fluid movement from the hepatorenal recess when you sit up
Fluid from the hepatorenal recess drains into the peritoneal gutter via the right parabolic gutter down to the retrocecal recess.
What gutter is the pathway for infection from the hepatorenal pouch into the pelvis?
The right paracolic gutter
Gastrosplenic ligament
Stomach to spleen
Gastrophrenic ligament
Stomach to diaphragm
At what vertebral level does the esophagus pierce the diaphragm
T10
What is the name of the hole the esophagus enters through the diaphragm
Esophageal hiatus
What does the abdominal portion of the esophagus “groove” before
The left lobe of the liver
What region of the stomach does the esophagus enter?
Cardiac oriface
Where along the esophagus is the structure covered in peritoneum
Lateral and anterior borders
What nerve plexus surrounds the esophagus
Esophageal plexus
What arteries supply the esophagus
Esophageal artery from left gastric artery of celiac trunk and inferior phrenic a.
What partially covers the stomach
ribs
Greater curvature of the stomach
Left boarder of the stomach notched where the esophagus enters (cardiac notch). Greater momentum attaches here
Lesser curvature of the stomach
Right border at the pyloric end contains the angular notch
What are the 4 different regions of the stomach
Cardiac antrum, fundus, body, and pylorus
Cardiac antrum
region joining esophagus
Fundus
Region superior and left of cardiac antrum demarcated by a horizontal plane through the cardiac oriface
Body
Major portion of the stomach
Pylorus
separate from the body by the angular notch of the stomach Divided into the pyloric antrum (wider) and pyloric canal which ends with a very thick band of smooth muscle the pyloric sphincter
Duodenum shape
C shaped loop
4 parts of duodenum
- Superior
- Descending
- Horizontal
- Ascending
What parts of the duodenum are secondarily retroperitoneal?
The superior and descending
What are the vertebral levels for each region of the duodenum
- Superior L1
- Descending L3
- Horizontal L3
- Ascending L2
What regions of the duodenum are forgut derivatives? What are the remaining regions a part of?
-Superior and descending are forget derivatives the remainder are midgut
What is the blood supply to the superior and descending portion of the duodenum?
Celiac trunk
What are the horizontal and ascending regions of the duodenum supplied by?
Superior mesenteric artery
What is another name for the superior region of the duodenum?
The duodenal bulb
Ampulla of Vater location
Descending suodenum
Ampula of Vater: What is it?
Region where the common bile duct and main pancreatic duct enter the descending duodenum
Major duodenual papilla
Marks the opening of the common bile and main pancreatic duct inside the duodenum
Where do duodenal ulcers typically occur
Superior and descending region above the major duodenal papilla
What mesentery suspends the jejunum and ileum
Mesentery proper
Location of the mesentery proper
Obliquely, inferior, and to the right of the duodenaljejunal fleecer to the left side of L2 vertebrae and to the right sacroiliac joint (next to midbody of L5)
What covers the jejunum and ilium anteriorly?
Greater omentum
What region of the abdomen contains the jejunum
Unbilical region
What region of the abdomen contains the ileum
Hypogastric and inguinal regions
Which is more muscular the jejunum or ileum?
Jejunum
What do the intestinal arteries from the superior mesenteric artery form
Arterial arcades and vasa recta
Differences in arterial arcades and vasa recta between the jejunum and ileum
The ileum has more complicated arterial arcades and shorter vasa recta
Pilcae circulares
Spiral folds of mucous membrane
Which has more pronounced plicate circulates the jejunum or ileum?
Jejunum
What are the different regions of the large intestine
Cecum, appendix, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum.
What parts of the large intestine have a mesentery
The transverse and sigmoid colon
Where does the large intestine begin
At the ileoceccal junction
At what point does the descending colon become the sigmoid colon
When it crosses the pelvic brim
Taenia Coli
Longitudinal muscle layer forms 3 stripes on surface of large intestine
Haustra
Sacculations of large intestine (can see well in radiographs)
Appendicies epiploicae
Fat-filled peritoneal sacs become filled with waste in dicerticulosis
What are the 2 fluxures present in the large intestine
Hepatic fluxure and splenic fluxure
Hepatic fluxure
Ascending to transverse colon
Splenic fluxure
Transverse to descending colon
Arterial supply to the large intestine
Branches off the inferior and superior mesenteric a.a
Where does the rectum start and end?
Starts: S3 and ends at anal canal
Gastric ulcer
Lesions of the wall of the stomach that may disrupt the splenic a. causing sever hemorrhage. Gastric juices can also be released into the omental bursa and cause periontitis
Appendicitis
Acute inflammation of the appendix
Ascites
Effusion of peritoneal cavity with fluid
Peritonitis
Inflammation of pariteoneal cavity
Adhesions
Scar tissue connecting parietal and visceral paritoneum
