Anatomy: Abdomen III - Peritoneum, Omentum and Ligaments

continuous, glistening, slippery & transparent serous membrane

the abdominalpelvic cavity & invests the viscera

1. parietal peritoneum - lines internal surface of abdominalpelvic wall

2. visceral peritoneum - invests viscera (i.e. stomach, intestines)

mesothelium

(a layer of simple squamous epithelial cells)

same somatic nerve supply as is the region of the wall it lines

pressure

pain

heat and cold

laceration

generally well localized

• except for that on the inferior surface of the central part of the diaphragm (innervation is provided by the phrenic nerve)

to the C3 - C5 dermatomes over the shoulder

the same blood and lymphatic vasculature and visceral nerve supply

insensitive to:

touch

heat and cold

laceration

stimulated primarily by:

** **stretching

chemical irritation

epigastric

umbilical

pubic

• poorly localized

• referred to the dermatomes of the spinal ganglia providing the sensory fibers

Intraperitoneal organs are almost completely covered with visceral peritoneum (e.g., the stomach and spleen)

Extraperitoneal, retroperitoneal, and subperitoneal organs are outside the peritoneal cavity “external, posterior, or inferior to the parietal peritoneum” and are only partially covered with peritoneum (usually on just one surface).

• between the parietal peritoneum and the posterior abdominal wall

• on their anterior surfaces

• between the parietal peritoneum and the posterior abdominal wall

• only on its superior surface

is within the abdominal cavity and continues inferiorly into the pelvic cavity

a potential space of capillary thinness

it’s is composed of water

electrolytes

other substances derived from interstitial fluid in adjacent tissues

• lubricates the peritoneal surfaces

• enables the viscera to move over each other without friction

• allows the movements of digestion

leukocytes and antibodies

absorbed by ymphatic vessels

(particularly on the inferior surface of the diaphragm)

males

through the uterine tubes, uterine cavity, and vagina

external infection

protective mechanisms of the female reproductive tract

• mucous plug

(blocks most things, excep sperm)

• normally present bacteria in vagina

(other bacteria cannot co-exist)

hysterosalpingography

• a technique in which air or radiopaque dye is injected into the uterine cavity

(normally flows through the uterine tubes and into the peritoneal cavity)

peritoneum is well innervated

(small, laparoscopic incisions or vaginal operations = less painful)

the covering of peritoneum (serosa)

extraperitoneal structures that have an outer adventitial layer

• high incidence of complications such as peritonitis and adhesions

contamination of the cavity

bacterial contamination = infection and inflammation of the peritoneum

• from a laparotomy, penetrated or rupturing of the gut

• allows gas, fecal matter, and bacteria to enter the peritoneal cavity

OR

ulcer perforates the wall of the stomach or duodenum

• spilling acid content into the peritoneal cavity.

• exudation (slow leaking) of serum, fibrin, cells, and pus into the peritoneal cavity

• pain in the overlying skin + increase in the tone of the anterolateral abdominal muscles

• the extent of the peritoneal surfaces

• rapid absorption of material (including bacterial toxins) from the peritoneal cavity

severe abdominal pain

tenderness

nausea and/or vomiting

fever

constipation

ridigity of abdominal walls

formation of any detergent-like substances (i.e. fatty acid + Na = soap) in cavity is lethal

1. superior border of diaphragm

2. liver

3. collected gases due to peritonitis

consumption of alcohol

clinical condition in which one has excess fluid in peritoneal cavity

(ascitic fluid)

• mechanical injury (may also produce internal bleeding)

• pathological conditions (i.e. portal hypertension=venous congestion)

• widespread metastasis of cancer cells to the abdominal viscera

• starvation (plasma proteins fail to be produced, alter concentration gradients = paradoxically protuberant abdomen)

rhythmic movements of the anterolateral abdominal wall

• If the abdomen is drawn in as the chest expands (paradoxical abdominothoracic rhythm)

- muscle rigidity is present

• lie with knees flexed = relax anterolateral abdominal muscles

• breath shallowly (+ more rapidly) = reducing the intra-abdominal pressure and pain

• peritoneum is damaged = surfaces become inflamed + sticky with fibrin

• as it heals, fibrin may be replaced with fibrous tissue

• forms abnormal attachments between visceral peritoneum of adjacent viscera

OR

between visceral peritoneum of viscera and parietal peritoneum of the adjacent abdominal wall

• may form after an abdominal operation

• limit normal movements of the viscera

• may cause chronic pain or emergency complications (i.e. intestinal obstruction when gut is twisted around an adhesion (volvulus))

surgical separation of adhesions

Treatment of generalized peritonitis

• removal of the ascitic fluid

• administration of large doses of antibiotics (if infection is present)

• occasionaly more localized accumulations of fluid removed for analysis

paracentesis = surgical puncture of the peritoneal cavity for the aspiration or drainage of fluid

• injection of a local anesthetic agent

• needle or trocar and a cannula are inserted through anterolateral abdominal wall into peritoneal cavity through the linea alba (for example)

• needle is inserted superior to the empty urinary bladder and in a location that avoids the inferior epigastric artery

• can be absorbed rapidly

• anesthetic agents injected into peritonal cavity

• semipermeable membrane

• extensive surface area

• overlies blood & lymphatic capillary beds

• soluble substances + excess water removed from system by transfer across the peritoneum

• use a dilute sterile solution introduced into peritoneal cavity on one side and drained from the other side

• solutes + water are transferred between blood and peritoneal cavity due to concentration gradients between the two fluid compartments

• usually only temporary; changes in mesothelial cells of peritoneum + underlying connective tissue = progressively ineffective

• double layer of peritoneum (invagination of the peritoneum by an organ) = continuity of the visceral and parietal peritoneum

• provides a means for neurovascular communication between the organ and the body wall

intraperitonel organ + body wall (usually posterior abdominal wall)

small intestine mesentery

mesenteries related to other specific parts of the alimentary tract are named accordingly

a core of connective tissue containing:

blood and lymphatic vessels

nerves

lymph nodes

fat

a double-layered extension (fold) of peritoneum that passes from:

stomach + proximal part of the duodenum

--->

adjacent organs in the abdominal cavity

prominent peritoneal fold that hangs down (like an apron) from the greater curvature of the stomach and the proximal part of the duodenum

• after descending: folds back +at taches to anterior surface of the transverse colon and its mesentery

• connects lesser curvature of the stomach and proximal part of the duodenum to the liver

• also connects the stomach to a triad of structures that run between the duodenum and liver in the free edge of the lesser omentum

a double layer of peritoneum that connects an organ with another organ or to the abdominal wall

• Anterior abdominal wall by the falciform ligament

• Stomach by the hepatogastric ligament

• (membranous portion of lesser omentum)*

• Duodenum by the hepatoduodenal ligament

• (thickened free edge of lesser omentum; conducts the portal triad)*

portal vein

hepatic artery

bile duct

the lesser omentum

• Inferior surface of diaphragm by the gastrophrenic ligament

• Spleen by the gastrosplenic ligament

(gastrolienal ligament; reflects to the hilum of the spleen)

• Transverse colon by the gastrocolic ligament

• the area on intraperitoneal organs NOT covered by visceral peritoneum

• allow entry/exit of mesenteries, omenta, and ligaments that convey the neurovascular structures

• reflection of peritoneum raised from the body wall by underlying blood vessels, ducts, and obliterated fetal vessels

• Some peritoneal folds contain blood vessels and bleed if cut

• (ex. lateral umbilical folds --> inferior epigastric arteries)*

a pouch of peritoneum formed by a peritoneal fold

• prevents the visceral peritoneum from adhering to the parietal peritoneum

• considerable mobility; moves around peritoneal cavity with peristaltic movements of the viscera

• often forms adhesions adjacent to an inflamed organ, sometimes walling it off = protecting other viscera

• also cushions the abdominal organs against injury + insulation against loss of body heat

circumscribed collection of purulent exudate in the subphrenic recess

can be caused by:

• perforation of a duodenal ulcer

• rupture of the gallbladder

• perforation of the appendix

abscess may be walled inferiorly by adhesions

recesses determine the extent and direction of the spread of fluids that may enter the peritoneal cavity when an organ is diseased or injured