Anatomy - The Peritoneal Cavity Flashcards
What is the epithelium lining of the abdominal cavity?
Simple squamous epithelium.
What is the peritoneal cavity?
A potential space between the visceral and parietal peritoneum. It is filled with peritoneal fluid.
What is a retroperitoneal organ?
An organ that only has it’s anterior surface covered by peritoneum. These organs lie behind the peritoneum.
Name 6 retroperitoneal organs.
Duodenum, ascending colon, descending colon, pancreas, oesophagus, kidneys. (DADPOK).
What is an intraperitoneal organ?
An organ fully covered in visceral peritoneum. It is suspended in the peritoneal cavity.
Name 6 intraperitoneal organs.
Sigmoid colon, appendix, liver, transverse colon, stomach, small intestine. (SALTSS).
What connects the lesser sac to the greater sac?
The epiploic foramen.
What does the lesser omentum attach to?
It extends from the liver and attaches to the lesser curvature of the stomach and the first part of the duodenum.
What is found in the right free border of the lesser omentum?
- Common bile duct. - Hepatic artery. - Hepatic portal vein.
Where is attached to the greater curvature of the stomach?
The greater omentum.
Describe the position and folding of the greater omentum in the peritoneal cavity.
It hangs down like an apron and then folds back on itself meaning there are 4 layers. The posterior 2 layers go on to enclose the transverse colon (transverse mesocolon) and then form the parietal peritoneum of the posterior abdominal wall.
What is it called when the peritoneal cavity becomes distended by fluid?
Ascites.
With a patient in a supine (lying down) position, where might fluid collect in the abdomen?
In the right retrohepatic space.
What embryological structure forms the ligamentum teres?
The umbilical vein.
Which structures surround the epiploic foramen?
- Anteriorly: lesser omentum. - Posteriorly: IVC. - Inferiorly: duodenum. - Superiorly: caudate lobe of liver.
What connects the jejunum to the posterior abdominal wall?
Small intestine mesentery.
What parts of the large intestine are intraperitoneal?
The transverse and sigmoid colon.
Define lesser sac.
A peritoneal sac that lies posteriorly to the stomach and lesser omentum. It communicates with the greater sac through the epiploic foramen.
What lies in the free border of the lesser omentum?
The hepatic artery, hepatic portal vein and common bile duct.
What structures lie posteriorly to the stomach?
Pancreas, diaphragm, splenic artery and vein.
What is the foregut supplied by? Where is its pain referred to?
- supplied by the greater Splanchnic nerve arising from T5-9
- felt anteriorly in the midline, ie epigastrium area
- (Oesophagus, stomach, pancreas, liver, gallbladder, duodenum)
What is the midgut supplied by? Where is its pain referred to?
- By the lesser splanchnic nerve, Arise from T10-11
- Pain is referred to the periumbical area
- (Duodenum distal to the entrance of the common bile duct to the junction of the proximal two thirds of the transverse colon)
What is the hindgut supplied by? where is its pain referred to?
- supplied by the lower splenetic nerve, arise from T12
- Pain is referred to the suprapubic area
- (Distal one third of the transverse colon to the upper part of the anal canal)
Describe referred pain of the diaphragm?
- sensory input from the phrenic nerve (C345)
- referred pain is in dermatomes of the shoulder
Describe referred pain of the abdomen?
- the peritoneal covering the inside of the abdominal wall has the same sensory nerve for supplies the skin overlying the same area
- therefore the pain is felt directly over the diseased area
- T5 to T10 is sternum to umbilicus
- T10 to 12 is to lower suprapubic area
Described the referred pain of the kidneys?
- Sensory innervation from the sympathetic plexus (T10,11,12)
- Pain radiates from the loin to the groin
- same plexus applies the gonad, so pain can be felt in no gonadal area and conversely gonadal pain can be felt in the loin
What does the peritoneal cavity contain?
- thin film of peritoneal fluid
- water, electrolytes, leucocytes, antibodies
- acts as a lubricant enabling free movement of the abdominal viscera and antibodies in the fluid fight infection
- The cells of the peritoneum trap a layer of mucus between their microvilli allowing for the viscera to slide freely
Name the two sacks the peritoneal cavity can be divided into?
- greater sac - comprises of the majority the peritoneal cavity
- the lesser sac - also known as the omenta bursa, lies posterior to the stomach and lesser omentum
Describe the two compartments of the greater sac divided into?
- divided by the mesentery of the transverse colon, Connected by the paracolic gutters
- supracolic - Lies above the transverse mesocolon, contains the stomach, liver and spleen
- infracolic - Lies below the transverse mesocolon contains the small intestines, ascending and descending
- further divided into the left and right intracolic Spaces by the mesentery of the small intestines
Describe the clinical relevance of the sub- phrenic abscess?
- sub- phrenic recesses are potential spaces in the supracolic compartment of the greater sac
- located between the liver and the diaphragm
- the left and right recess is separated by the falciform ligament of the liver
- Sub- phrenic abscesses, the buildup of pus in these spaces, most common on the right side due to appendicitis and ruptured duodenal ulcers
Describe the anatomy and functions of the lesser sac?
- posterior to the stomach and lesser omentum
- allows the stomach to move freely
- Form due to the twisting of the foregut during embryonic development
What connects the greater and lesser sac?
- the epiploic foramen (of Winslow)
- situated posterior to the free edge of the lesser omentum
What is the peritoneum?
- Continuous membrane which lines the abdominal cavity and abdominal organs
- provides pathways for blood vessels and lymph the travel to and from the viscera
- Consists of two layers that are continuous with each other, the parietal peritoneum and the visceral peritoneum
- both are made up of simple squamous epithelial cells called mesothelium
Describe parietal peritoneum?
- Lines the internal surface of the abdominal pelvic wall
- derived from the somatic mesoderm of the embryo
- Well localised pain, pressure, laceration and temperature
Describe visceral peritoneum?
- Covers the majority of the abdominal viscera
- derived from the splenetic mesoderm of the embryo
- Same autonomic supplies the viscera above it
- Poor localised pain, Only sensitive distraction chemical irritation
- pain is referred to dermatomes of the skin
What are the intraperitoneal organs?
- Enveloped by the visceral peritoneum
- Stomach, liver and spleen
What are the retroperitoneal organs?
- They are not associated with the visceral peritoneum, they are only covered in parietal peritoneum (only covers their anterior surface)
- There are two groups based on the embryological development:
- primary retroperitoneal - Develop and remain outside the parietal peritoneum (the oesophagus, rectum and kidneys)
- secondary retroperitoneal - Initially intraperitoneally, but their mesentery fused with the posterior abdominal wall (ascending and descending colon)
What is the mesentery?
- a double layer of visceral peritoneum
- connects all intraperitoneally organs to the posterior abdominal wall
- to the small intestines it’s called the mesentery, but other parts it’s named according to the viscera it connects to
What is the omentum? Describe its two parts?
- Sheets of visceral peritoneum extending from the stomach and proximal part of the duodenum To all other abdominal organs
- the greater omentum
- consists of four layers of visceral peritoneum,
- descends from the greater curvature of the stomach and the proximal part of the duodenum,
- then fold back up and attaches to the anterior surface of the transverse colon
- Has a role in immunity, migrates towards infected viscera
- the lesser omentum
- double layer of visceral peritoneum
- attaches from the lesser curvature of the stomach and the proximal part of the duodenum to the porta hepatis (where the portal vein and hepatic artery and to the liver, and the bile leaves in the bile duct)
- two parts:
- the Hepatogastric ligament ( flat broad Sheet)
- the hepatoduodenal ligament (free edge, containing the portal triad)
What are peritoneal ligaments?
- it’s double fold at the peritoneum that connects together visceral or viscera to the abdominal wall
What is the clinical relevance of Ascites?
- accumulation of excess fluid within the peritoneal cavity
- typically caused by portal hypertension or liver cirrhosis
- clinical features include abdominal distension, abdominal discomfort, nausea, and dyspnoea ( due to pressure on the lungs)
What is the urachus? What is found either side of it?
- embryological remnants allows urine to flow out of the umbilicus
- Either side are remnants of the paired umbilical arteries
- extending from the superior vesicle Artery to the umbilicus
What is the left triangular ligament?
- a double layer peritoneum attaching the left lobe of the liver to the inferior surface of the diaphragm
- The entire left lobe is above the costal margin and cannot be palpated transabdominally
How is the spleen attached to the greater curvature of the stomach and the posterior abdominal wall?
- by folds in the peritoneum forming part of the greater omentum
What is the clinical relevance of bacteria in the abdomen?
- Source of infection
- tend to gravitate towards the lowest part
- behind the right lobe of the liver when lying flat
- into the pelvis when upright
Describe the clinical relevance of peritoneal dialysis?
- the peritoneum is semipermeable
- patients with renal failure can draw waste products from the blood into the peritoneal cavity
Which parts of the bowel have a mesentery?
- the 1st cm of the duodenum
- all of the jejunum and ilium
- The transverse and sigmoid colon
- The appendix
You are examining a patient with a large spleen. How do you know on examination that you are palpating the spleen?
- Located in the upper left quadrant. - Unable to feel an upper border on palpitation.
What structure is the median arcuate ligament related to?
The aorta.
What muscle is the medial arcuate ligament related to?
Psoas major.
What muscle is the lateral arcuate ligament related to?
Quadratus lumborum.
