1. Regions of abdominal
For the purpose of description clinicians use planes
to refer nine regions of the abdominal cavity to
describing the location of the organs
They use four planes two horizontal and two vertical
The nine regiona are:
3. Regions and their contents
Right Hypochondriac Epigastric Left Hypochondriac
Right & Left Adrenal
Right & Left Kidneys
Right & Left Kidneys
Right & Left Ureters
Pancreas (tail of)
4. Right lumber umbilicus Left lumber
Right & Left Kidneys
Right & Left Kidneys
Right & Left Ureters
Left Kidney (tip)
Left Kidney (tip)
5. Right iliac hypo gastric Left iliac
Cecum & Ascending
Right & Left Ovaries
Right & Left Ureters
Right & Left Ovaries
Right & Left Fallopian
Right Ovary (Females)
6. Abdominal Wall & Cavity
The abdomen is the part of the trunk inferior to the
Its musculomembranous walls surround a large cavity
(the abdominal cavity)
is bounded superiorly by the diaphragm and inferiorly
by the pelvic inlet.
The abdominal cavity may extend superiorly as high
as the fourth intercostal space, and is continuous
inferiorly with the pelvic cavity.
It contains the peritoneal cavity and the abdominal
7. LAYERS OF THE ABDOMINAL WALL
(external to internal):
2. Superficial fascia (or subcutaneous tissue)
3. Muscles and associated fascia
4. Parietal peritoneum
The Superficial Fascia
Above the umbilicus: A single sheet of connective tissue. This continuous with the
superficial fascia in other regions of the body.
Below the umbilicus: It is divided into two layers; the fatty superficial layer (Camper’s
fascia) and the membranous deep layer (Scarpa’s fascia). Superficial vessels and
nerves run between these two layers of fascia.
Muscles of the Abdominal Wall
There are five muscles in the abdominal wall. They can be divided into two groups:
Vertical muscles – There are two vertical muscles, situated near the mid-line of the body.
the Rectus Abdominis and Pyramidalis.
Flat muscles – There are three flat muscles, situated laterally.
the external oblique, internal oblique and transversus abdominis.
8. ABDOMINAL VISCERA AND
Visceral peritoneum is a thin membrane (the peritoneum) lines the walls of
the abdominal cavity and covers much of the viscera.
The parietal peritoneum lines the walls of the cavity and the visceral
peritoneum covers the viscera.
Between the parietal and visceral layers of peritoneum is a potential space (the
Abdominal viscera either are suspended in the peritoneal cavity by folds of
peritoneum (mesenteries) or are outside the peritoneal cavity.
Organs suspended in the cavity are referred to as intraperitoneal; organs
outside the peritoneal cavity, with only one surface or part of one surface
covered by peritoneum, are retroperitoneal.
The peritoneal cavity is subdivided into the greater sac and the omental
bursa (lesser sac) :
I. The greater sac accounts for most of the space in the peritoneal cavity, beginning superiorly
at the diaphragm and continuing inferiorly into the pelvic cavity.
II. The omental bursa is a smaller subdivision of the peritoneal cavity posterior to the stomach
and liver and is continuous with the greater sac through an opening, the omental (epiploic)
The esophagus is a tubular structure that joins the
pharynx to the stomach. The esophagus pierces the
diaphragm slightly to the left of the midline and
after a short course of about 0.5 inch. (1.25 cm)
enters the stomach on its right side. It is deeply
placed, lying behind the left lobe of the liver
It is a straight muscular tube connecting the oral
cavity to the stomach
It is about 25cm long and 2cm wide
11. The esophagus is a muscular canal, about 23 to 25
cm. long, extending from the pharynx to the
stomach. It begins in the neck at the lower border of
the cricoid cartilage, opposite the sixth cervical
vertebra, descends along the front of the vertebral
column, through the superior and posterior
mediastinum, passes through the diaphragm, and,
entering the abdomen, ends at the cardiac orifice of
the stomach, opposite the eleventh thoracic vertebra.
13. Esophageal constrictions
Normally, the esophagus has three anatomic
constrictions at the following levels.
1-At the esophageal inlet, where the pharynx joins the
esophagus, behind the cricoid cartilage (14-16 cm from
the incisor teeth).
2-Where its anterior surface is crossed by the aortic
arch and the left bronchus (25-27 cm from the incisor
3-Where it pierces the diaphragm (36-38 cm from the
The distances from the incisor teeth are important as is
useful for diagnostic endoscopic procedures.
14. Gastro esophageal junction
The junction between the esophagus and the stomach (the
gastro esophageal junction or GE junction) is not actually
considered a valve, although it is sometimes called the cardiac
sphincter, cardia or cardias, it actually better resembles a
In much of the gastrointestinal tract, smooth muscles
contract in sequence to produce a peristaltic wave which
forces a ball of food (called a bolus) while in the esophagus. In
humans, peristalsis is found in the contraction of smooth
muscles to propel contents through the digestive tract.
The stomach is a dilated part of the
alimentary canal between the esophagus
and the small intestine. It occupies the left
upper quadrant, epigastric, and umbilical
regions, and much of it lies under cover of
the ribs. Its long axis passes downward and
forward to the right and then backward and
17. The stomach lies between the oesophagus and the
duodenum (the first part of the small intestine). It is on
the left upper part of the abdominal cavity. The top of
the stomach lies against the diaphragm. Lying behind
the stomach is the pancreas. The greater omentum
hangs down from the greater curvature.
Two sphincters keep the contents of the stomach
contained. They are the esophageal sphincter (found in
the cardiac region, not an anatomical sphincter) dividing
the tract above, and the Pyloric sphincter dividing the
stomach from the small intestine.
19. The stomach is surrounded by parasympathetic (stimulant)
and orthosympathetic (inhibitor) plexuses (networks of blood
vessels and nerves in the anterior gastric, posterior, superior
and inferior, celiac and myenteric), which regulate both the
secretions activity and the motor (motion) activity of its
In adult humans, the stomach has a relaxed, near empty
volume of about 45 ml. Because it is a distensible organ, it
normally expands to hold about 1 litre of food, but can hold
as much as 2-3 liters. The stomach of a newborn human baby
will only be able to retain about 30ml.
20. Sections of Stomach
The stomach is divided into 4 sections, each of which
has different cells and functions. The sections are:
Where the contents of the esophagus empty into the stomach.
Formed by the upper curvature of the organ.
Body or Corpus
The main, central region.
The lower section of the organ that facilitates emptying the
contents into the small intestine.
23. Small intestine
The small intestine is the longest part of the
gastrointestinal tract and extends from the pyloric
orifice of the stomach to the ileocecal fold. This hollow
tube, which is approximately 6-7 m long with a
narrowing diameter from beginning to end, consists of
the duodenum, the jejunum, and the ileum.
The first part of the small intestine is the duodenum.
This C-shaped structure, adjacent to the head of the
pancreas, is 20-25 cm long and is above the level of
the umbilicus; its lumen is the widest of the small
intestine . It is retroperitoneal except for its
beginning, which is connected to the liver by the
hepatoduodenal ligament, a part of the lesser
The duodenum is divided into four sections
3. inferior part
4. ascending part
26. The superior part (first part) extends from the
pyloric orifice of the stomach to the neck of the
The descending part (second part) of the
duodenum is just to the right of midline and
extends from the neck of the gallbladder to the
lower border of vertebra LII. This part of the
duodenum contains the major duodenal
papilla, which is the
common entrance for the bile and pancreatic
ducts,and the minor duodenal papilla,
27. The inferior part (third part) of the duodenum
is the longest section, crossing the inferior vena cava
the aorta, and the vertebral column .
The ascending part (fourth part) of the
duodenum passes upward on, or to the left of, the
aorta to approximately the upper border of vertebra
LII and terminates at the duodenojejunalflexure.
The jejunum represents the proximal two-fifths. It
is mostly in the left upper quadrant of the abdomen
and is larger in diameter and has a thicker wall than
the ileum. Additionally, the inner mucosal lining of
the jejunum is characterized by numerous prominent
folds that circle the lumen
Ileum makes up the distal three-fifths of the small
intestine and is mostly in the right lower quadrant.
The ileum opens into the large intestine where the
cecum and ascending colon join together.
34. Large intestine
The large intestine extends from the distal end of
the ileum to the anus, a distance of approximately
1.5 m in adults. It absorbs fluids and salts from the
gut contents, thus forming feces, and consists of
the cecum, appendix, colon, rectum.
37. Cecum and appendix
The cecum is the first part of the large intestine It is
inferior to the ileocecal opening and in the right iliac
fossaThe cecum is continuous with the ascending
colon at the entrance of the ileum and is usually in
contact with the anterior abdominal wall.
The appendix is a narrow, hollow, blind-ended tube
connected to the cecum. It has large aggregations of
lymphoid tissue in its walls and is suspended from
the terminal ileum by the mesoappendix , which
contains the appendicular vessels.
The colon extends superiorly from the cecum and
consists of the ascending, transverse,descending, and
sigmoid colon . Its ascending and descending segments
are retroperitoneal and its transverse and sigmoid
segments are intraperitoneal. The final segment of the
colon (the sigmoid colon) begins above the pelvic inlet
and extends to the level of vertebra SIII, where it is
continuous with the rectum . This S-shaped structure is
quite mobile except at its beginning, where it continues
from the descending colon.
39. Rectum and anal
Extending from the sigmoid colon is the rectum . The
rectosigmoid junction is usually described as being at
the level of vertebra SIII or at the end of the sigmoid
mesocolon because the rectum is a retroperitoneal
structure. The anal canal is the continuation of the
large intestine inferior to the rectum.
40. Anatomy of Liver
The liver is a reddish brown organ with four lobes
of unequal size and shape. A human liver normally
weighs 1.4–1.6 kg (3.1–3.5 lb), and is a soft, pinkish-
brown, triangular organ. It is both the largest
internal organ (the skin being the largest organ
overall) and the largest gland in the human body.
It is located in the right upper quadrant of the
abdominal cavity, resting just below the diaphragm.
The liver lies to the right of the stomach and overlies
43. The biliary tree&Biliary Flow
The term biliary tree is derived from the arboreal branches of the
bile ducts. The bile produced in the liver is collected in bile
canaliculi, which merge to form bile ducts. Within the liver, these
ducts are called intrahepatic (within the liver) bile ducts, and once
they exit the liver they are considered extrahepatic (outside the
liver). The intrahepatic ducts eventually drain into the right and left
hepatic ducts, which merge to form the common hepatic duct. The
cystic duct from the gallbladder joins with the common hepatic duct
to form the common bile duct.
Bile can either drain directly into the duodenum via the common
bile duct, or be temporarily stored in the gallbladder via the cystic
duct. The common bile duct and the pancreatic duct enter the
second part of the duodenum together at the ampulla of Vater.
45. the liver is Divided into four lobes based on surface features. The falciform ligament
is visible on the front (anterior side) of the liver. This divides the liver into a left
anatomical lobe, and a right anatomical lobe.
If the liver is flipped over, to look at it from behind (the visceral surface), there are
two additional lobes between the right and left. These are the caudate lobe (the
more superior) and the quadrate lobe (the more inferior).
From behind, the lobes are divided up by the ligamentum venosum and ligamentum
teres (anything left of these is the left lobe), the transverse fissure (or porta hepatis)
divides the caudate from the quadrate lobe, and the right sagittal fossa, which the
inferior vena cava runs over, separates these two lobes from the right lobe.
Each of the lobes is made up of lobules; a vein goes from the centre, which then
joins to the hepatic vein to carry blood out from the liver.
On the surface of the lobules, there are ducts, veins and arteries that carry fluids to
and from them.
he gallbladder is a hollow system that sits just beneath
the liver.In adults, the gallbladder measures
approximately 8 cm in length and 4 cm in diameter when
fully distended. It is divided into three sections: fundus,
body and neck. The neck tapers and connects to the
biliary tree via the cystic duct, which then joins the
common hepatic duct to become the common bile duct.
The angle of the gallbladder is located between the costal
margin and the lateral margin of the rectus abdominis
48. Parts of Gall Bladder
The gall bladder is consisting of the following parts if
seen from below upwards and also backwards: the
fundus, body, and the neck. Each of them is given a
brief description below:
Funds: the lower free and the expanded end of the
Gall bladder is known as the fundus of the gall
bladder. It is projection from below the liver and its
direction is downwards, forwards, and also to the
right where it comes in contact with the anterior wall
of the abdomen where it makes an angle of about
Body: the body of the gall bladder is the portion that
is lying between that of the funds and also the neck.
The direction of the body is upwards, backwards, and
to the left.
Neck: it is the “S” shaped curve present above the
body, and extends up to the cystic duct. Direction is
upwards, forwards and then takes a turn and
becomes downwards and backwards. Sometimes
there is a presence of some diverticulum’s known as
the Hartmann’s pouch and this portion is often
termed as the isthmus of the gall bladder.
53. Anatomy of Spleen
spleen, in healthy adult humans, is approximately
11 centimeters (4.3 in) in length. It usually weighs
between 150 grams (5.3 oz) and 200 grams (7.1 oz)
and lies beneath the 9th to the 12th thoracic ribs.
57. Relationship of the Kidneys to Vertebra and Ribs
They are retroperitoneal
and are located in the
They are at the level of
T12 to L3, so they are at
the costal margin, and the
ribs protect them a little.
Even though they are
protected by thoracic
ribs, they are NOT in the
thoracic cavity because
they are below the
The kidney has a bean-shaped structure, each kidney has
concave and convex surfaces. The concave surface, the renal
hilum, is the point at which the renal artery enters the organ,
and the renal vein and ureter leave. The kidney is surrounded
by tough fibrous tissue, the renal capsule, which is itself
surrounded by perinephric fat , renal fascia (of Gerota) and
The superior border of the right kidney is adjacent to
the liver; and the spleen, for the left border.
Therefore, both move down on inhalation.
The kidney is approximately 11–14 cm in length,
6 cm wide and 4 cm thick.
It weighs about 150 Grams.
The Superior part of the kidney has a suprarenal
the ureters are muscular tubes that propel urine from the
kidneys to the urinary bladder. In the adult, the ureters are
usually 25–30 cm (10–12 in) long and ~3-4 mm in diameter.
In humans, the ureters arise from the renal pelvis on the
medial aspect of each kidney before descending towards the
bladder on the front of the psoas major muscle. The ureters
cross the pelvic brim near the bifurcation of the iliac arteries
(which they run over). This is a common site for the impaction
of kidney stones (the others