Chapter 3 - Abdominal Cavity and Peritoneum Flashcards
9 regions of abdomen
- Right hypochondrium
- Left hypochondrium
- Epigastric
- Right lumbar
- Left lumbar
- Umbilical
- Right iliac fossa
- Left iliac fossa
- Hypogastric
Transpyloric plane
- horizontal plane
- passes midway b/w suprasternal notch and pubic symphysis
- anteriorly, passes through tip of 9th coastal cartilage
- posteriorly, through body of L1 vertebra
Transtubercular plane
- horizontal plane
- through tubercles of iliac crest and body of L5
Lateral planes
- correspond to midclavicular lines
- pass through midinguinal point
Histological composition of peritoneum
- outer layer of fibrous tissue - gives strength
- inner layer of mesothelial cells - secrete serous fluid to lubricate viscera
Parietal peritoneum
- Lines inner surface of abdomen and pelvic walls and lower surface of diaphragm
- Derived from somatopleuric layer of lateral plate mesoderm
- Pain sensitive due to somatic innervation
Visceral peritoneum
- Firmly adherent to outer surface of viscera
- Derived from splanchnopleuric layer of lateral plate mesoderm
- Evokes pain when viscera is stretched, ischemic or distended
Folds of peritoneum
- Degree and direction of mobility of organ governed by size and direction of folds
- Provide pathway for passage of vessels, nerves and lymphatics
- Form ligaments to connect organs to abdominal wall or to each other
Peritoneal cavity
- potential space b/w adjacent layers of peritoneum
- thin film of serous fluid present secreted by mesothelial cells
- fluid helps in lubrication and free movement
- divided into greater sac and lesser sac which communicate through epiploic foramen
- recesses separated from main cavity are present
Functions of peritoneum
- Provides slippery surface for movements of viscera
- Contains phagocytic cells for both cellular and humoral immunity
- Greater omentum can move towards area of infection to prevent spread
- Mesothelium acts as semipermeable membrane to allow passage of solutes and water
- Mesothelial cells can transform into fibroblasts for healing of wounds
- Capable of storing large amounts of fat
Causes of ascites
Collection of free fluid in peritoneal cavity
- Liver cirrhosis
- Tubercular peritonitis
- Congestive heart failure
- Malignant infiltration of peritoneum
Inflammation of peritoneum
Peritonitis
Presence of air in peritoneal cavity
Pneumoperitoneum
May occur after perforation of stomach or intestines
Artery of foregut, midgut and hindgut
Foregut: Coeliac
Midgut: Superior mesentric
Hindgut: Inferior mesenteric
Foregut forms
Oesophagus
Stomach
Upper part of duodenum
Midgut forms
Duodenum, jejunum, ileum Appendix Caecum Ascending colon 2/3 transverse colon
Hindgut forms
1/3 transverse colon
Descending colon
Sigmoid colon
Proximal rectum
Ventral mesogastrium
- Ventral mesentery that suspends abdominal part of foregut
- Divided by liver into dorsal and ventral
Ventral part
- falciform ligament
- right and left triangular ligaments
- coronary ligament
Dorsal part
- lesser omentum
Dorsal mesogastrium
- Caudal part forms greater omentum
- Cranial gets divided into ventral and dorsal by spleen
Ventral: gastrosplenic ligament
Dorsal: lienorenal ligament - Cranialmost part forms gastrophrenic ligament
Greater omentum define
- Large fold of fperitoneum that hangs down from greater curvature of stomach
- Made of 4 fused layers of peritoneum
Greater omentum attachments
- Ant. 2 layers descend from greater curvature of stomach and fold upon themselves
- Post. 2 layers ascend to anterior surface of body of pancreas
- 4th layer is partially fused to ant. surface of transverse colon and transverse mesocolon
Contents of Greater omentum
- Right and left gastroepiploic vessels
2. Fat
Functions of Greater omentum
- Stores fat
- Protects cavity from infection (milky spots of macrophages)
- Limits infection
- Forms partition b/w supra and infracolic compartments
Lesser omentum define
- extends from lesser curvature of stomach and duodenum to liver
Hepatogastric ligament: portion b/w stomach and liver
Hepatoduodenal lig.: b/w duodenum and liver - has a free right margin in front of epiploic foramen
Attachments of lesser omentum
Inferiorly: lesser curvature of stomach and upper border of duodenum
Superiorly: liver
Contents of lesser omentum
- Proper hepatic A
- Portal V
- Bile duct
- Lymph nodes
- Hepatic plexus of N
- Right and left gastric vessels
- Gastric lymph nodes
- Gastric nerves
Define mesentery
- broad, fan-shaped fold of peritoneum
- suspends coils of jejunum and ileum
Borders of mesentery
- attached border extends from duodenojejunal flexure to right sacroiliac joint
- it crosses:
Abdominal aorta
Inferior vena cava
Right ureter
Right psoas major - free border is in pleats forming visceral peritoneum of gut
Contents of mesentery
- Jejunal and ileal branches of superior mesenteric A
- Accompanying V
- Autonomic nerve plexuses
- Lacteals
- 100-200 lymph nodes
- Fat
Mesoappendix
- small triangular fold of peritoneum
- suspends vermiform appendix
- reaches tip of appendix
- contains vessels, nerves, lymph nodes and lymphatics
Features of transverse mesocolon
- broad fold of peritoneum
- suspends transverse colon from upper part of posterior abdominal wall
Attachments of transverse mesocolon
- root attached to anterior surface of head and anterior body of pancreas
Contents of transverse mesocolon
- Middle colic vessels
- Nerves
- Lymph nodes
- Lymphatics
Features of sigmoid mesocolon
- triangular fold of peritoneum
- suspends sigmoid colon from pelvic wall
Attachments of sigmoid mesocolon
- V shaped root
- apex lies over left ureter
- left limb attached along upper half of left external iliac A
- right limb to posterior pelvic wall
Contents of sigmoid mesocolon
- Sigmoid vessels
2. Superior rectal vessels, N, lymph nodes, lymphatics
Describe epiploic foramen
- vertical slit like opening through which lesser sac communicates with greater sac
- situated behind right free margin of lesser omentum
- level of T12 vertebra
Boundaries of epiploic foramen
A: Right free margin of lesser omentum containing portal V, proper hepatic A, bile duct
P: IVC, T12, right adrenal gland
S: Caudate process of liver
I: Duodenum, hepatic A
Features of lesser sac
- recess of peritoneal cavity behind stomach, lesser omentum and liver
- closed except in upper part of right border for epiploic foramen
Anterior boundaries of lesser sac
- Peritoneum of liver
- Posterior layer of lesser omentum
- Peritoneum covering posterior surface of stomach
- 2nd layer of greater omentum
Posterior boundaries of lesser sac
- 3rd layer of greater omentum
- Peritoneum covering transverse colon
- Upper layer of transverse mesocolon
- Peritoneum covering pancreas, left adrenal, left kidney, splenic vssels, diaphragm
Other boundaries of lesser sac
Upper: reflection of peritoneum of diaphragm
Lower: Right margin og greater omentum
Right: Epiploic foramen
Left: Left margin of greater omentum
Intraperitoneal spaces of supracolic compartment
- left anterior
- left posterior
- right anterior
- right posterior
Extraperitoneal spaces of supracolic compartment
- right extraperitoneal
- left extraperitoneal
- middle extraperitoneal
Left anterior and posterior spaces
LAS - b/w left lobe of liver and diaphragm - extends to front of lesser omentum - reaches spleen towards left LPS = Lesser sac
Right anterior and posterior spaces
RAS - b/w right lobe of liver and diaphragm - in front of coronary and right triangular ligament RPS - hepatorenal pouch of Morrison
Right, left and middle extraperitoneal spaces
RES
- around upper pole of right kidney
LES
- around left suprarenal gland and upper pole of left kidney
MES
- b/w bare area of liver and diaphragm
- bounded by superior and inferior layers of coronary ligament
Boundaries of hepatorenal pouch of Morrison
A: 1. inferior surface of liver 2. Gall bladder P: 1. Right adrenal 2. Right kidney 3. 2nd part of duodenum 4. Hepatic flexure of colon 5. Transverse mesocolon 6. Head of pancreas S: inferior layer of coronary ligament I: peritoneal cavity RIGHT: Diaphragm LEFT: Omental bursa
Right and left infracolic compartments
RIC - b/w ascending colon and mesentery - triangular with apex downwards LIC - b/w descending colon and mesentery - triangular with apex directed upwards
