Abdomen 2: Peritoneal cavity Flashcards
What is the abdominal cavity space bounded by?
- Diaphragm
- Anterolateral abdominal wall
- Posterior abdominal wall
- Pelvic inlet
What is visceral peritoneum?
Visceral peritoneum is when the peritoneum touches the organ
What is the parietal peritoneum?
Parietal peritoneum is when the peritoneum doesn’t touch the organ
What does peritoneal fluid in the peritoneal cavity contain?
-Peritoneal fluid contains water, electrolytes, interstitial fluid, leukocytes and antibodies
What is type of cavity is the peritoneum in males?
In males, peritoneum is a closed cavity
What type of cavity is the peritoneum in females?
In females, peritoneum is an open cavity as there’s communication with the exterior via the vagina, uterus and uterine tubes
What is a peritoneum?
A thin, serous membrane lining the abdominal and pelvic cavities
What does the parietal peritoneum line?
Lines the walls of the abdominal and pelvic cavities
What is the parietal peritoneum sensitive to?
- Pain
- Temperature
- Touch
- Pressure
What is the parietal peritoneum innervated by?
Innervated by somatic spinal nerves from T7-L1
What does the visceral peritoneum line?
Lines the abdominal and pelvic organs/viscera
What is the visceral peritoneum sensitive to?
- Stretch
- Tearing
What does over distention of the viscera lead to?
Over distention of the viscera leads to sensation of pain
What is the visceral peritoneum innervated by and what implications can arise due to the way its innervated?
- Innervated by afferent nerves that travel with autonomic supply to viscera it covers
- Referred pain implications
What is a dermatome?
Dermatome is an area of skin supplied by one spinal nerve root
How are sensory inputs from visceral organs interpreted by the brain as?
Sensory input from visceral organs is interpreted by the brain as originating from one of the midline dermatomes
What do dermatomes share a convergent spinal root with?
Dermatomes share a convergent spinal root with the autonomic nerve which supplied that
What nerve gives a sympathetic supply to the foregut?
Greater splanchnic nerves T5-T9(T10)
What nerve gives a sympathetic supply to the midgut?
-Lesser splanchnic nerves T9-T11(T12)
What nerve gives a sympathetic supply to the hindgut?
Lumbar splanchnic nerves L1-L2
Convergence example of T7 and visceral organ
- If someone touches the skin at T7, the epigastric region, it activates the somatic sensory nerve from the dermatome
- It then comes to the level T7
- Also at T7, we have nerve roots running from the greater splanchnic nerve which travels down to the organ ,so in this case the stomach
- The cutaneous nerve converges with the autonomic nerve
- If the stomach is stretched, the visceral peritoneum is also stretched travelling with the greater splanchnic nerve, hitchhiking along is the visceral afferent, a sensory nerve from the visceral peritoneum and it converges into the same spinal nerve root as the dermatome
- If pain is coming from the visceral peritoneum, it interprets it as its coming from the epigastric region, hence the converging pain.
How are organs like with intraperitoneal organs?
Organs are completely covered with visceral peritoneum
How are organs attached to each other or to the abdominal wall?
Organs are attached to each other or to the abdominal wall by a double fold of peritoneum:
- Mesentery
- Ligaments
- Omentum
What is the mobility like for intraperitoneal organs?
Organs have greater mobility
How are extraperitoneal organs like?
Organs are partially or entirely devoid of peritoneum
Where do extraperitoneal organs lie?
They lie outside peritoneal cavity
What can extraperitoneal organs be according to its position?
- According to position, they can be:
- Retroperitoneal
- Sub-peritoneal
- Organs are slightly movable or immovable
What does secondary retroperitoneal mean?
Secondary retroperitoneal means during the embryological development, they were intraperitoneal but then migrated backwards and the visceral peritoneum split, making the organ retroperitoneal
What are the fold of the peritoneal structure?
A reflection of peritoneum that connects organs to another organ or to the abdominal wall:
- Omenta - Mesenteries - Ligaments
What are folds of the peritoneum raised from the body wall by?
A reflection of peritoneum that is raised from the body wall by underlying blood vessels, duct and ligaments formed by obliterated foetal vessels
What is the function of peritoneal folds?
- Route of blood vessels, lymphatic, nerves.
- May contain embryological remnants
- E.g. Falciform ligament of liver: Umbilical vein
- Contains varying amount of fat
- Greater omentum (high volume)
- Lesser omentum (devoid of fat)
- May contain intraperitoneal parts of organs
- Tail of pancreas lies in splenorenal ligament
- Immunity
- Greater omentum: Policeman of abdomen
- Prevents effects of gravity
What is the mesentery?
double fold of peritoneum
What is the developing foregut suspended from the anterior body wall by?
by ventral mesentery/mesogastrium
What is the developing foregut suspended from the posterior body wall by?
by dorsal mesentery/mesogastrium
Where does the liver start to develop?
Liver starts to develop in ventral mesentery
What does the peritoneal cavity split the ventral mesentery into?
Splits ventral mesentery into:
- Lesser omentum (Passing from liver to stomach) - Falciform ligament (Passing from liver to anterior abdominal wall)
What does the stomach rotate around during embryological development of peritoneal cavity and where do the pyloric and cardiac parts move?
- Pyloric part moves to right and upwards
- Cardiac part moves to the left and downwards
Where is the dorsal mesogastrium pulled to, what does it trap and what is this known as?
Dorsal mesogastrium is pulled to the left, trapping part of the peritoneal cavity behind the stomach and this is known as the lesser sac/omental bursa
An incision through what enters the peritoneal cavity?
A surgical incision through the anterior abdominal wall enters into the greater peritoneal sac
Where is the lesser sac?
Space posterior to stomach
What does the lesser sac allow?
Allows stomach to expand
What does the lesser sac communicate with the greater sac through?
Communicates with greater sac through epiploic foramen of Winslow
What is the lesser omentum?
Double fold of peritoneum that connects the inferior surface of the liver to the lesser curvature of the stomach and first part of duodenum
Where does the portal triad run relative to of the lesser omentum?
Portal triad runs in free edge of lesser omentum (hepatoduodenal ligament)
What does the portal triad consist of?
- Common bile duct
- Proper hepatic artery
- Hepatic portal vein
What is the epiploic foramen the opening into ?
Opening into lesser sac (Omental Bursal)
What is the superior boundary of the epiploic foramen?
-Superior: Caudate process of liver
What is the inferior boundary of the epiploic foramen?
1st part of duodenum
What is the posterior boundary of the epiploic foramen?
Inferior vena cava and right crus of diaphragm
What is the anterior boundary of the epiploic foramen?
Portal triad(in free edge of lesser omentum)
What is the greater omentum?
Double fold of peritoneum folded back on its self(four layers), forming an apron like structure that hangs from the greater curvature of the stomach
What is the greater omentum formed from?
Formed from a downwards extension of the dorsal mesogastrium
What layers fuse to form the greater omentum?
Anterior layers and posterior layers fuse to form greater omentum
What can surgeons do to the layers of the greater omentum to give access to the lesser sac and what recess is the access through?
Layers can be separated by surgeons to give passageway into the lesser sac through the inferior recess
What is a transverse mesocolon?
Double fold of peritoneum that connects transverse colon to the posterior abdominal wall
What is the anterior layer of the transverse mesocolon attached to?
Anterior layer of transverse mesocolon is attached to the posterior layer of greater omentum
What is the mesentery?
Fan-shaped double fold of peritoneum that suspends the jejunum and ilium from the posterior abdominal wall
What does the mesentery contain?
- 1 Superior mesenteric artery
- 2 superior mesenteric veins
What is the approximate length of the root of the mesentery?
Approx 15cm long
What is the course of the root of the mesentery?
Oblique course
