APC2 Flashcards
What are the boundaries of the abdominopelvic cavity?
Superior: diaphragm
Inferior: pelvic diaphragm
Anterior/lateral: abdominal muscles/bony pelvis
Posterior: vertebral column, bony pelvis, iliopsoas, fascia
- How does peritoneum line the walls of the APC?
2. What exists between the parietal peritoneum and the overlying muscles of the walls?
- Parietal peritoneum lines walls except where it leaves to invest organs. In most regions, parietal peritoneum loosely attached to allow for alteration in size/position of certain organs, and movement of the walls. In some situations, firmly bound to wall.
- Fibro-fatty connective tissue
What is the blood supply, lymphatic drainage and nerve supply of peritoneum?
Visceral peritoneum: same as those of the viscus of which it covers
Parietal: same as those of the associated abdominopelvic wall
Visceral peritoneum innervated by autonomic nerves
Parietal pertioneum = somatic innervation
Therefore stimuli causing pain in GI tract and associated visceral peritoneum not the same as stimuli causing pain in body wall or associated parietal peritoneum
What are examples of retroperitoneal and secondary retroperitoneal?
Retro:
aorta/IVC, kidneys, nerve trunks, lower 2/3rds rectum, iliac arteries
2ndary retro:
pancreas (except tail), ascend/descend colon, duodenum (2nd-4th)
What are examples of intraperitoneal organs?
Tail of pancreas Small intestines Appendix/caecum Liver Stomach Transverse colon Duodenum - 1st part Rectum upper third Spleen Sigmoid colon
What are three peritoneal structures?
1) Mesentery/mesocolon = double layers attaching small intestine (mesentery), transverse colon and sigmoid colon (mesocolon) to PAW
2) Omentum: two double layers originating from ventral and dorsal mesogastria - greater between stomach and PAW (superficial to small intestine), lesser between stomach and PAW
3) Ligaments (or folds): bands of peritoneum which lie between viscera and body wall - no relation to ligaments surrounding joints
What is significant about peritoneal folds?
In some parts of abdomen may form recesses or fossae of the peritoneal cavity e.g. around duodenojejunal flexure and caecum
Fossae of little importance, but it is possible for loop of intestine to get trapped within on - resulting in intestinal obstruction
Do cutting or pressure cause pain in peritoneum?
Parietal sensitive to all types of stimuli - pain from the PP is well localised and it is sensitive to pressure, pain, laceration and temperature
Visceral peritoneum has same nerve supply as the viscera it invests - pain from the VP is poorly localised and only sensitive to stretch and chemical irritation. Pain from the VP is referred to dermatomes which are supplied by the same sensory ganglia and spinal cord segments as the nerve fibres innervating the viscera
Where do the following mesentery lie?
1) Jejunum and ileum
2) Transverse colon (mesocolon)
3) Sigmoid colon (mesocolon)
1) Attached diagonally across PAW from duodenojejunal flexure on left side of body of second vertebra –> right iliac region
2) Attached horizontally across PAW from anterior aspect of right kidney across descending part of duodenum, to pancreas
3) Inverted V shape - apex is near the bifurcation of the left common iliac artery
Why must care be taken when removing sigmoid colon?
Underneath the sigmoid mesocolon: external iliac vessels (apex is near left common iliac division), left piriformis, and left sacral plexus of nerves, left ureter descends into pelvis behind its apex
Sigmoid and superior rectal vessels run between the layers of the sigmoid mesocolon
What is the lesser omentum?
Derived from ventral mesogastrium - lies between visceral surface of liver and lesser curvature of stomach
From oesophageal end where it is reflected to undersurface of diaphragm, to pyloric end where it is attached to duodenum and PAW
Right edge = ‘free edge’ (anterior layer loops back on itself to become posterior layer at 1ST PART DUODENUM), - encloses the 3 structures en route to liver (biliary ducts, hepatic artery, hepatic portal vein)
What is the greater omentum? (course, development)
1) From dorsal mesogastrium (embryological structure connecting caudal foregut to PAW)
2) Connects stomach & PAW, lies in greater sac
- Visceral layers covering anterior & posterior stomach come together at greater curvature, forming 2 descending (anterior) layers of GO
3) At lower free border of GO, 2 layers fold back on themselves & pass superiorly as the ascending (posterior) layer - these 2 layers become continuous with PP on PAW
- During development the 4 layers of GO become fused
Inferior to attachment at PAW =transverse mesocolon attachment (transverse mesocolon and colon lie posterior to GO, during development GO fuses with it (lifting GO also lifts transverse colon)
What does the greater omentum consist of?
Fat (variable amount)
Gastroepiploic vessels which supply the stomach and omentum
Lymphatic vessels
What are possible functions of the greater omentum?
Fat deposition (varying amounts of adipose tissue) Immune contribution (milky spots of macrophage collection) Infection and wound isolation- may physically limit spread of intraperitoneal infection
What is the lesser sac?
Pouch of peritoneal cavity:
Posterior to liver/lesser omentum/stomach
Anterior to structures on the PAW
Lesser and greater sacs together comprise peritoneal cavity
What is the aditus to the lesser sac?
Epiploic foramen
Where lesser sac is continuous with greater sac
Posterior to free margin of lesser omentum
What is the superior boundary of the lesser sac?
Small recess which extends upwards as far as the diaphragm
What is the inferior boundary of the lesser sac?
In embryonic life - extends between descending and ascending layers of the greater omentum
Fusion of these layers during development - lesser sac becomes obliterated to a level just below the greater curvature of the stomach
What is the anterior wall of the lesser sac?
Liver, lesser omentum, posterior wall of stomach and small portion of greater omentum
What is the posterior wall of the lesser sac?
Bounded by part of the posterior abdominal wall & adherent portions of the greater omentum, covering the transverse colon and the transverse mesocolon
What is the right boundary of the lesser sac?
Initial part of right margin of greater omentum and aditus to lesser sac