Abdomen IV - Peritoneum, Omentum, Epiploic Spaces, Ligaments, Abdominal Viscera & Esophagus Flashcards
Embryology of the Peritoneal Cavity:
“By the end of the 10th week, the gut is much longer than the body that contains it.”
What 2 things are needed for this increase in length to occur?
- gut needs freedom of movement relative to the body wall
- maintain the connection with body wall necessary for innervation and blood supply
The embryological growht of the gut is accomodated by what?
development of the peritoneal serous cavity within the trunk
(houses the increasingly lengthy + convoluted gut in a relatively compact space)
During embryonic growth, why does the gut extend outside of the trunk for a period of time?
rate of growth of the gut initially surpasses the development of adequate space within the trunk
When does the midgut herniate into the umbilical chord?
early in week 5
The primary rotation of the herniated midgut occurs around what structure in the umbilical cord?
superior mesenteric srtery
The herniated midgut returns to the trunk by what time?
by the end of week 10
(by week 11)
During early development, the embryonic body cavity (intraembryonic coelom) is lined with what tissue?
What peritoneal structre is derived from this tissue?
- mesoderm
- the parietal peritoneum is derived from mesoderm
- (forms a closed sac)*
retroperitoneal structures…
…protrude only partially into the peritoneal cavity (partially covered by visceral peritoneum)
Intraperitoneal structures…
…protrude completely into the peritoneal cavity (completely covered by viseral peritoneum)
- connected to abdominal wall by mesentery
In general, viscera that vary relatively little in size and shape are….
retroperitoneal
In general, viscera that undergo changes in size/shape (filling/emptying, peristalsis) are…
invested with visceral peritoneum (intraperitoneal)
- they are mobile to some degree (b/c of mesentaries)
The vessels & nerves of intraperitoneal organs remain connected to what?
their extraperitoneal sources
What major change occurs in regards to the peritoneal cavity space from embryonic development to post-natal life?
changes from the 1. peritoneal cavity
(entire primordial gut is suspended)
to 2. potential space between the parietal + visceral layer
(organs have grown therefore space has been reduced)
As a result of growing organs, several parts of the gut come to lie against the posterior abdominal wall. What does this cause?
- their posterior mesenteries become gradually reduced because of pressure from overlying organs
What happens to the part of the visceral peritoneum lying against the body wall?
fuses with the parietal peritoneum of the body wall
During development, the peritoneal cavity is divided into what sections?
greater and lesser peritoneal sacs
A surgical incision through the anterolateral abdominal wall enters the main, larger part of the peritoneal cavity. Which sac is this?
the greater sac
What sac, also known as the omental bursa, lies posterior to the stomach and lesser omentum?
The lesser sac
The transverse mesocolon (mesentery of the transverse colon) divides the abdominal cavity into what 2 compartments?
What does each compartment contain?
supracolic compartment
- stomach
- liver
- spleen
infracolic compartment
- small intestine
- ascending + descending colon
The infracolic compartment lies posterior to what structure?
It is divided into what 2 spaces by the mesentery of the small intestine?
the greater omentum
- right infracolic space
- left infracolic space
How does free communication occur between the supracolic and the infracolic compartments?
through the paracolic gutters
(grooves between the lateral aspect of ascending or descending colon + posterolateral abdominal wall)
What is the omental bursa?
an extensive sac-like cavity that lies posterior to the stomach, lesser omentum, and adjacent structures
What are the names and locations of the 2 recesses of the omental bursa?
superior recess
limited superiorly by diaphragm + posterior layers of coronary ligament of liver
inferior recess
between superior parts of the layers of greater omentum
What permits free movement of the stomach on the structures posterior and inferior to it?
How does it do this?
The omental bursa
anterior and posterior walls of omental bursa slide smoothly over each other
Most of the inferior recess of the bursa becomes sealed off from the main part posterior to the stomach after what occurs?
adhesion of the anterior + posterior layers of the greater omentum
The omental bursa communicates with the greater peritoneal sac through what structure?
How can this structure be found?
the omental foramen (epiploic foramen)
- opening situated posterior to free edge of lesser omentum (hepatoduodenal ligament)*
- can be located by running a finger along gallbladder to the free edge of the lesser omentum
(usually admits two fingers)
What are the superior, inferior, anterior and posterior borders of the omental foramen?
Superiorly = liver, covered with visceral peritoneum
Inferiorly = superior (first) part of the duodenum
Anteriorly = hepatoduodenal ligament (free edge of the lesser omentum), containing portal vein, hepatic artery, + bile duct
Posteriorly = IVC + right crus of diaphragm (covered anteriorly with parietal peritoneum - retroperitoneal)
What results form a perforation of the posterior wall of the stomach?
passage of its fluid contents into the omental bursa
What pathology can also result in the passage of fluid into the bursa, forming a pancreatic pseudo-cyst?
An inflamed or injured pancreas
What uncommon abnormality may enter the omental bursa and be strangulated by the edges of the foramen?
How is this corrected?
a loop of small intestine may pass through the omental foramen
- swollen intestine must be decompressed using a needle so it can be returned to the greater peritoneal sac through the omental foramen
- (boundaries of the foramen can be incised because each contains blood vessels)*
During cholecystectomy (removal of the gallbladder), what must be done to the cystic artery?
What may happen to the cystic artery during this procedure?
cystic artery must be ligated or clamped and then **severed **
- Sometimes accidentally severed before it is adequately ligated
What can be done if the cystic artery is severed before it is properly ligated?
- can control the hemorrhage by compressing the hepatic artery as it traverses the hepatoduodenal ligament
- index finger is placed in the omental foramen and the thumb on its anterior wall
- alternate compression + release of pressure on hepatic artery allows surgeon to identify the bleeding artery + clamp it
The principal viscera of the abdomen are the…?
- terminal part of esophagus + stomach
- intestines
- spleen
- pancreas
- liver
- gallbladder
- kidneys
- suprarenal (adrenal) glands
What abdominal viscera almost fill the domes of the diaphragm?
Where do they receive protection from?
liver, stomach, spleen
- protected by lower thoracic cage
What ligament normally attaches along a continuous line to the anterior abdominal wall as far inferiorly as the umbilicus and divides the liver superficially into right and left lobes?
falciform ligament
The fat-laden greater omentum, when in its typical position, conceals almost all of …?
the intestine
The gallbladder projects inferior to …?
the sharp border of the liver
Food passes from the mouth and pharynx through the ___________ to the stomach, where it mixes with ______________?
esophagus
- gastric secretions -
Digestion mostly occurs in which areas?
the stomach and duodenum
Peristalsis
- series of ring-like contraction waves that begin around the middle of stomach + move slowly toward the pylorus
- responsible for mixing the masticated (chewed) food mass with gastric juices + emptying contents of stomach into duodenum
The stomach is continuous with what inferior structure?
This structure receives the openings of the ducts from _________?
the duodenum
- pancreas + liver (major glands of the digestive tract)
Absorption of chemical compounds occurs principally in what area?
This consists of what 3 parts?
small intestine
(coiled 5- to 6-m-long tube)
- duodenum
- jejunum
- ileum
What occurs in the jejunum and ileum but is not forceful unless an obstruction is present?
Peristalsis
The large intestine consists of what structures?
cecum
receives the terminal part of the ileum
appendix
colon
ascending, transverse, descending + sigmoid
rectum
anal canal
which ends at the anus
Most reabsorption of water occurs in what part fo the large intestine?
Feces form in what parts of the large intestine, before accumulating in the rectum?
water absorption = ascending colon
Fecal formation = descending + sigmoid colon
The arterial supply to the alimentary tract is from what source?
What are the three major branches from this that supply the gut?
abdominal aorta
- celiac trunk
- superior mesenteric arteries
- inferior mesenteric arteries
Which venous system collects blood from the abdominal part of the alimentary tract, pancreas, spleen, + most of the gallbladder?
portal venous system
The portal vein is formed by the union of what 2 veins?
It carries blood from the abdominal part of the alimentary tract and some viscera to where?
superior mesenteric + splenic veins
- to the liver
Esophagus
- muscular tube [approximately 25 cm long]
- average diameter of 2 cm
- conveys food from the pharynx to the stomach
- normally has three constrictions where adjacent structures produce impressions (seen in barium swallow)
What are the 3 constrictions of the esophagus?
Cervical constriction:
- beginning at pharyngoesophageal junction, approx 15 cm from incisor teeth
- caused by cricopharyngeus muscle
- clinically = upper esophageal sphincter
Thoracic (broncho-aortic) constriction:
- compound constriction where first crossed by arch of aorta (22.5 cm from incisor teeth)
- where it is crossed by left main bronchus (27.5 cm from incisor teeth)
- former is seen in anteroposterior views, latter in lateral views
Diaphragmatic constriction:
- passes through the esophageal hiatus of diaphragm (approx 40 cm from incisor teeth)
What is the clinical importance of an awareness of the diaphragmatic constrictions?
- passing instruments through the esophagus into the stomach
- viewing radiographs of patients who are experiencing dysphagia (difficulty in swallowing)
The esophagus follows the curve of what?
(as it descends through the neck and mediastinum)
Has internal circular and external longitudinal layers of muscle.
In its superior third, the external layer consists of voluntary striated muscle; the inferior third is composed of smooth muscle, and the middle third is made up of both types of muscle.
vertebral column
musculature of the esophagus
- internal circular + external longitudinal layers of muscle
- superior 1/3 = external layer consists of voluntary striated muscle
- inferior 1/3 = smooth muscle
- middle 1/3 = both types of muscle
Where does the esophagus pass into the abdomen?
- elliptical esophageal hiatus in muscular right crus of the diaphragm
(just to left of median plane at T10 vertebra level)
Where does the esophagus terminate inferiorly?
enters stomach at cardial orifice of the stomach
(left of midline at 7th left costal cartilage + T11 vertebra level)
The esophagus is encircled distally by what structre?
esophageal nerve plexus
The esophagus is attached to the margins of the esophageal hiatus in the diaphragm by …?
phrenicoesophageal ligament
(extension of inferior diaphragmatic fascia)
- permits independent movement of diaphragm + esophagus during respiration and swallowing
What causes food to pass through the esophagus rapidly?
** peristaltic action** (aided by gravity)
The abdominal part of the esophagus is located where?
How long is it?
- from esophageal hiatus –> cardial orifice of the stomach
- (passing anteriorly + left as it descends)*
- 1.25 cm long
The anterior surface of the esophagus is covered with what?
** peritoneum of the greater sac**
(continuous with that covering the anterior surface of the stomach)
The posterior surface of the esophagus is covered with what?
peritoneum of the omental bursa
(continuous with that covering the posterior surface of the stomach)
The esophagus fits into a groove on the posterior (visceral) surface of what organ?
the liver
The right border of the esophagus is continuous with the ______________?
The left border is separated from the fundus of the stomach by the ______________?
- lesser curvature of the stomach
- cardial notch
The esophagogastric junction lies where?
left of the T11 vertebra
( on horizontal plane passing through tip of xiphoid process)
@ Z-line
(jagged line where mucosa abruptly changes fr. esophageal to gastric mucosa)
immediately inferior to:
“physiological inferior esophageal sphincter”
(contracts and relaxes)
What structure prevents the reflux of gastric contents into the esophagus?
sphincter mechanism
When one is not eating, what happens to the lumen of the esophagus?
- normally collapsed superior to the esophagogastric junction to prevent food or stomach juices from regurgitating into the esophagus
The arterial supply of the abdominal part of the esophagus is from what 2 arteries?
left gastric artery (branch of celiac trunk)
left inferior phrenic artery
The venous drainage from the submucosal veins of the abdominal part of the esophagus is to which 2 venous systems (through which veins)?
portal venous system –> left gastric vein
systemic venous system –> esophageal veins entering azygos vein
The lymphatic drainage of the abdominal part of the esophagus is into which lymph nodes?
left gastric lymph nodes
(efferent lymphatic vessels from these nodes drain mainly to celiac lymph nodes)
The esophagus is innervated by the (1.)___________ plexus, formed by the (2.)_______ trunks and the (3.)___________ trunks via the (4.)______________ nerves and (5.)___________ plexuses around the left gastric and inferior phrenic arteries.
1 - esophageal nerve plexus
2 - vagal trunks
(becoming anterior and posterior gastric branches)
3 - thoracic sympathetic trunks
4 - greater (abdominopelvic) splanchnic nerves
5 - periarterial plexuses
Because the submucosal veins of the inferior esophagus drain to both the portal and the systemic venous systems, they constitute a ___________________?
portosystemic anastomosis
What happens in portal hypertension (an abnormally increased blood pressure in the portal venous system)?
blood is unable to pass through the liver via the portal vein, causing a reversal of flow in the esophageal tributary
The large volume of blood in portal hypertension causes the submucosal veins to enlarge markedly, forming what?
esophageal varices
What life-threatening occurance can result from esophageal varices?
Who is most likely to develop varacies?
- varicies may rupture + cause severe hemorrhage that is life-threatening and difficult to control surgically
- commonly develop in alcoholics who have developed cirrhosis (fibrous scarring) of the liver
This is the most common type of esophageal discomfort or substernal pain:
(clinical + common name)
Pyrosis or heartburn
Pyrosis:
The burning sensation in the abdominal part of the esophagus is usually the result of …?
regurgitation of small amounts of food or gastric fluid into the lower esophagus (gastroesophageal reflux disorder)
which type of hernia may be associated with pyrosis?
hiatal (hiatus) hernia
