it is a detail explanation about abdominal anatomy

1. Anatomy of the abdomen
• Abdominal cavity
• Anterolateral abdominal wall
• Peritoneum and peritoneal cavity
• Abdominal viscera
• Digestive system organs
• Spleen
• Urinary system organs
• Posterior abdominal wall

2. Introduction
•Abdomen is part of the trunk between the thorax and the
pelvis
•It is a flexible, dynamic container, housing most of the
organs of the digestive system and part of the urogenital
system
•The abdomen is able to enclose and protect its contents
while allowing the flexibility between the more rigid thorax
and pelvis required by respiration, posture, and locomotion

3. Abdominal cavity
• Located between the diaphragm and the pelvic inlet
• Separated from the thoracic cavity by diaphragm
• Continuous inferiorly with the pelvic cavity
• Undercover of thoracic cage superiorlyextend to 4th intercostal space
• Supported and partially protected inferiorlyby the greater pelvis
• Enclosed anterolaterally by multi-layered, musculoaponeurotic,
abdominal walls
• Lined with peritoneum

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5. Regions of abdomen
• Clinicians subdivide abdomen into 9 regions to locate
abdominal organs, pain sites, swelling or incision
• Delineated by 4 planes
• Two horizontal
• Subcostal plane: passing through inferior border of 10th
costal cartilage
• Transtubercular plane: passing through iliac tubercles
body of L5 vertebra
• Two vertical
• Midclavicular planes: passing from midpoints of
to midinguinal points

7. Regions of abdomen
• For general clinical descriptions, clinicians divide abdomen
into 4 quadrants defined by 2 planes
• Transumbilical plane: passing through umbilicus and disc
between L3 and L4 vertebrae
• Median plane: longitudinal plane dividing the body into
right and left halves

9. Abdominal aorta:Location
• Continuation of thoracic aorta
• Lies in the midline against vertebral bodies
• It enters the abdomen through aortic hiatus at T12
and L1 level
• Ends at L4, left of the midline by dividing into the 2
common iliac arteries.
• The main continuation of the aorta is the median or
middle sacral artery

11. Abdominal aorta: Branches
• Subdivided into groups of 4:
• 3 unpaired visceral
• paired visceral
• paired parietal
• unpaired parietal

13. Unpaired visceral branches
• Ventral branches; arise from
anterior surface
• Celiac trunk
• Superior mesenteric
• Inferior mesenteric
• Coeliac trunk:
• Foregut oesophagus to
Duodenum 2nd part
• Superior mesenteric
• Midgut Duodenum 3rd part
to distal 1/3 transverse colon
• Inferior mesenteric
• Hindgut distal 1/3
transverse colon to upper 2/3
of rectum

14. Inferior Vena Cava
• Returns blood from
lower limbs, abdominal
wall and
abdominopelvic
viscera
• Begins in front of the
body of L5 by union of
common iliac veins
• Pierce the central
tendon at T8 forming
vena caval foramen

15. Tributaries
• Ventral tributary: right testicular or ovarian vein
• Lateral tributaries: renal and right suprarenal and
hepatic veins
• The left where the suprarenal and gonadal veins
open into the left renal vein
• Tributaries from the body wall: the inferior phrenic
and lumbar veins
• the median sacral opens into the left common iliac vein

16. Lymphatic drainage
• Lymph from the posterior abdominal wall drain into
right and left lumbar lymph nodes (lie along the
aorta, IVC)
Efferent lymphatic vessels from the large lumbar
lymph nodes form the right and left lumbar
lymphatic trunks.
Thoracic Duct
Cisterna
chyli

18. Peritoneum and peritoneal cavity
• All ventral body cavities contain serous membranes
• It lines the abdominopelvic cavity and invests the viscera
• Two layers
•Visceral peritoneum: covers the external surface of most digestive organs
•Parietal peritoneum: lines the walls of the abdominopelvic cavity

19. • The parietal peritoneum is served by the same blood and lymphatic
vasculature and the same somatic nerve supply as is the region of
the wall it lines
• Parietal layer is sensitive to pressure, pain, heat and cold, and
laceration
• The visceral peritoneumand the organs it covers are served by the
same blood and lymphatic vasculature and visceral nerve supply.
• The visceral layer is insensitive to touch, heat, cold, and laceration
• Visceral layer is stimulated primarily by stretching and chemical
irritation

20. Peritoneal cavity
•Between the two layers is the peritoneal cavity,
•A slit like potential space containing fluid secreted by the
serous membranes
•The serous fluid lubricates the mobile digestive organs,
allowing them to glide easily across one another as they
carry out their digestive activities

21. Peritoneal and retroperitoneal organs
• Intraperitoneal organs are almost completely covered with visceral
peritoneum (e.g., stomach and spleen).
• Extraperitoneal, retroperitoneal, and subperitoneal organs are also
outside the peritoneal cavity—external to the parietal
peritoneum—and are only partially covered with peritoneum
• E.g. kidneys

23. Peritoneal folds
• Peritoneum contains large folds that weave between viscera
• The folds binds organs to each other and to the walls of abdominal cavity
Mesentery
• A double layer of peritoneum that encloses small intestine to the posterior
abdominal wall
• Mesenteries provide routes for blood vessels, lymphatics and nerves to
reach the digestive viscera
• Mesenteries also suspendthe visceral organs in place as well as serving as a
site for fat storage

24. Cont…
• The small intestine mesentery is usually referred to simply as “the
mesentery”;
• however, mesenteries related to other specific parts of the alimentary
tract are named accordingly—for example,
 Transverse and sigmoid mesocolons
 Mesoesophagus
 Mesogastrium
 Mesoappendix

26. Omentum
• Is a double-layered extension or fold of peritoneum that passes
fromthe stomachand proximal part of the duodenum to adjacent
organs in the abdominal cavity
Greater omentum
• Is a prominent, four-layered peritoneal fold that hangs down like an
apron from the greater curvature of the stomach and the proximal
part of the duodenum
• After descending, it folds backand attaches to the anterior surface of
the transverse colon and its mesentery.

28. Lesser
sac

30. lesser omentum
• Is a much smaller, double-layered peritoneal fold
• It connects the lesser curvature of stomach and proximal part of
duodenum to the liver.
• The lesser omentum contains the major hepatic vessels –bile duct,
portal vein, hepatic artery and gastric vessels
• Its free edge forms the boundary between the greater and lesser sacs
at the omental foramen

33. • Falciform ligament: a double layer of peritoneum that connects the liver with
the anterior abdominal wall.

34. • Transverse mesocolon and transverse colon divides peritoneal cavity
into Supracolic and Infracolic compartments
Subdivisions of peritoneal cavity

35. Supracolic compartment
• Containing the stomach, liver, and spleen
Infracolic compartment
• containing the small intestine and ascending and descending colon
• lies posterior to the greater omentum

36. Division of Peritoneal cavity
• The peritoneal cavity is divided
into the greaterand lesser
peritoneal sacs.
• The greater sac is the main and
larger part of the peritoneal
cavity.
• The omental bursa(lesser sac) lies
posterior to the stomach and
lesser omentum
• Communication of greater sac
and lesser sac is through omental
foramen (epiploic foramen)

37. Function:
•The digestive system performs 6 basic processes:
• Ingestion: taking in food
• Secretion: water, acid, buffers and enzymes
• Mixing and propulsion: mix food and secretions and move materials
• Digestion: break down food into nutrient molecules
• Absorption: entrance of the nutrient molecules into the bloodstream
• Defecation: removal of indigestible remains
The Digestive system

38. Organs
• The organs of the GIT
• Mouth
• Pharynx
• Esophagus
• Stomach
• Small and large
intestine
• The accessory digestive
organs
• Teeth
• Tongue
• Salivary glands
• Gallbladder
• Liver
• Pancreas

39. General description of digestive
process
• Absorption of nutrients occurs principally in the small
intestine
• Most reabsorption of water occurs in the ascending colon.
• Feces form in the descending and sigmoid colon &
accumulate in the rectum before defecation.
• Peristalsis, a series of ring-like contraction waves,
begins around the middle of the stomach and moves
slowly toward the pylorus.
Function
• Mixing the masticated (chewed) food mass with gastric
juices

40. Esophagu
s
• Joins stomach at gastroesophageal junction
 Muscular tube, food passage
between pharynx and stoma
ch
 Has about-25 -30 cm long
 Extends from the level of C6-
T11
 2-3 cm in the abdominal cavi
ty
Three part
 Cervical
 Thoracic
 Abdominal
Pierces the diaphragm at the le

41. Arterial supply
1. Cervical part– inferior thyroid arteries
2. Thoracic part – esophageal branches of thoracic aorta
3. Abdominal part – esophageal branches of left gastric arter
y
Venous drainage
1. Upper part – brachiocephalic veins
2. Middle part – azygos veins
3. Lower end – left gastric vein (portal drainage)

42. Nerve supply – autonomic
Parasympathetic
 Upper ½ - recurrent laryngeal nerve
 Lower ½- esophageal plexus (formed by the two vagi)
Sympathetic
upper ½ - middle cervical ganglion
Lower ½- upper 4 thoracic ganglia (esophageal plexus)
Lymphatic drainage
•Cervical – deep cervical lymph nodes
•Thoracic- posterior mediastinal lymph nodes
•Abdominal – left gastric lymph nodes

43. Stomach
• The stomach is involved in the whole range of
digestive activities
• Serves as a holding area for ingested food
• Breaks down food further chemically and mechanically
• Delivers chyme to the small intestine at a controlled rate
• Produce HCL, pepsin, protein digesting enzyme
• Is the J-shape sac & most expandable parts of
digestive tract that stored, mixes, & digests the
ingested nutrients.
• Digestion mostly occurs in the stomach and
duodenum

45. Stomach: Gross Anatomy
•The diameter and volume of stomach depend on how much
food it contains
•Empty may contain 500 ml
•But can expand to hold about 4 liters of food
•When empty, the stomach collapses inward, throwing its
mucosa into large, longitudinal folds called rugae
•Is covered entirely by peritoneum

46. Stomach
• In supine position it
located in the left upper
quadrant at the left
hypochondriac and
epigastric regions of the
abdomen.
• 4 major region of the
stomach
• Cardia:
• Fundus:
• Body:
• Pyloric region:
•2 curvatures
Greater and lesser
curvatures

48. Stomach: Blood supply
• Rich blood supply
• Arterial supply
• From celiac trunk and its branches
• The arterial arch on the lesser curvature is formed
by
• Right and left gastric arteries
• The arterial arch on the greater curvature is
formed by
• Right and left gastro-omental
(gastroepiploic) arteries
• Fundus and upper body receive blood from short

51. Venous drainage: Gastric veins parallel the arteries
• Left and right gastric veins drain into portal vein
• Short gastric veins & left gastro-omental veins drain into
splenic vein
• Right gastro-omental vein drain into superior mesenteric
vein
Innervation
Parasympathetic
Anterior vagal trunk and Posterior vagal trunk
• Sympathetic – T6-T9 through greater splanchnic
nerves
Gastric lymph nodes and
Gastro-omental lymph
nodes
Celiac lymph
• Lymph from stomach drains
into

54. Small Intestine
• Major digestive organ
• In the small intestine, usable food is finally prepared
for its journey into the cells of the body
• Here digestion is completed and virtually all
absorption occurs
• However, this vital function cannot be accomplished
without the aid of secretions from the liver (bile) and
pancreas (digestive enzymes)

55. Small Intestine
• Convoluted tube extending from pyloric sphincter in
the epigastric region to the ileocecal valve
• It is the longest part of the alimentary tube, but
its diameter is only about 2.5 cm
• In cadaver, the small intestine is 6 - 7 m long
because of loss of muscle tone, while it is only 2 - 4 m
long in living individual.
• Has three subdivisions
• Duodenum
• Jejunum
• Ileum

56. Duodenum
• C- shaped
• Curves about the head of the pancreas
• The shortest, widest and most fixed part of
small intestine
• It extend from the pylorus to the
duodenojejunal flexure
• Has about 25 cm length
• Is retroperitoneal except the first part

58. Parts of
duodenum
• First part
• Duodenal cap or bulb
• Second (descending) part
• where the bile duct and
pancreatic duct join the
duodenum through the
ampulla of Vater
• Third part (inferior or
transverse)
• Fourth part (ascending)

59. Duodenum
Features associated with Duodenum
• Bile duct: receive bile from the liver
• Main pancreatic duct: carries pancreatic juice from the
pancreas
• Hepatopancreatic ampulla: union of bile duct and main
pancreatic duct in the wall of the duodenum
• Sphincter of Oddi: at opening of hepatopancreatic ampulla
• Major duodenal papilla: elevation formed when
hepatopancreatic ampulla enters the duodenum

61. Arterial Supply of Duodenum
• Celiac artery
Gastroduodenal artery: Superior Pancreaticoduodenal
• Superior Mesenteric artery: Inferior Pancreaticoduodenal (Anterior and
Posterior)

62. The veins of the duodenum follow the arteries and drain into the
hepatic portal vein, some directly and others indirectly, through
the superior mesenteric and splenic veins

63. The nerves of the duodenum derive from the vagus and greater
and lesser (abdominopelvic) splanchnic nerves by way of the
celiac and superior mesenteric plexuses.
• The anterior lymphatic
vessels drain into the
pancreaticoduodenal
lymph nodes,
• Then to pyloric lymph
nodes
• The posterior lymphatic
vessels drain into
superior mesenteric
LN
Lymphatic drainage

64. Jejunum
Mainly in left upper quadrant
Responsible for absorbing most of the intestinal
contents
2 ½ meters long
Extends from the duodenum to the ileum
Twists back and forth within the abdominal cavity
Makes up the proximal 2/5th of the small intestine

65. Ileum
Is longer than the jejunum
More in right lower quadrant of abdomen
3 ½ meters in length
No sharp division from the jejunum
Specialised function is to absorb bile salts and
vitamin B12
Joins the caecum at the ileocecal valve
The jejunum and ileum are suspended from the
posterior abdominal wall by the fan shaped mesentery

66. • The jejunum and ileum hang in coils in the central
and lower part of the abdominal cavity

67. Small Intestine: blood supply
Arterial supply
• Superior mesenteric artery: supplies the
jejunum and ileum via jejunal and ileal
arteries
Venous drainage
• The veins run parallel to the arteries and
drain into superior mesenteric vein
• From the mesenteric vein, the nutrient rich
venous blood from the small intestine drains
into the hepatic portal vein which carries it
to the liver

69. • Specialized lymphatic vessels in the intestinal villi that absorb
fat are called lacteals
• They empty their milk-like fluid into the lymphatic plexuses in
the walls of the jejunum and ileum
• Within the mesentery, the lymph passes sequentially through
three groups of lymph nodes
 Juxta-intestinal lymph nodes
 Mesenteric lymph nodes
 Superior central nodes
• Efferent lymphatic vessels from the mesenteric lymph nodes
drain to the superior mesenteric lymph nodes
Lymphatic vessels

70. Small Intestine: innervation
• Parasympathetics: from the vagus nerves
• Sympathetic: from the splanchnic nerves
These are relayed through the superior mesentericand celiac plexus

71. Large Intestine
• The large intestine frames the small intestine on
three sides and extends from the ileocecal valve
to the anus
• About 1.5 meters long
• Two main functions:
1. Reabsorption of water and electrolytes from
indigestible food residues to turn semi liquid small
intestinal contents into formed faeces
2. Store & eliminate stool from the body as semisolid
feces

72. Over most of its
length, the large
intestine exhibits
three features
• Teniae coli
• Haustra
• Epiploic appendages

74. • Teniae coli
• Three bands (narrow strap) of smooth muscle that run
the length of the large intestine
• Because the teniae (= ribbon or tape) are shorter than
the intestine the colon becomes sacculated between the
teniae forming “haustra”
• The teniae fuse at the appendix (useful in locating the
appendix)
• Haustra
• Pocket like sacs formed by the tonic contraction of the
teniae coli
• Epiploic appendages
• Small fat-filled pouches of visceral peritoneum that hang
from its surface
• Small, fatty, omentum-like projections
• Significance is not known

75. Large Intestine: subdivisions
• Cecum with appendix
• Colon
• Ascending colon
• Transverse colon
• Descending colon
• Sigmoid colon
• Rectum
• Anal canal

76. Cecum
• The first part of the large intestine
• Saclike blind pouch
• Lies below the ileocecal valve in the right iliac fossa
• It is an intraperitoneal structure
• The cecum is continuous with the ascending colon
at the entrance of the ileum
• The appendix is attached to the posteromedial wall
of the cecum, just inferior to the end of the ileum

77. Appendix
•Is a blind intestinal diverticulum and
•Narrow hollow muscular tube which connected to the cecum
by a triangular mesentery mesoappendix
•Contains the appendicular vessels, large masses of lymphoid
tissue, short and few glands
•Has about 6-10 cm in length
•Has no teniae coli
•Because it is blind-ended, its contents are not renewed
rapidly thus it becomes a frequent site of inflammation =
appendicitis

78. • 1/3 of the way along a
line from the anterior
superior iliac spine to the
McBurney’s point
• The appendix is
normally situated at
McBurney’s point
• Innervation lower thoracic
part of the spinal cord, and
vagus nerves via the
superior mesenteric plexus

79. Location appendix
•Is highly variable.
•It may be found:
• (1%)
• (0.5)
• (64%)
• (32%)
• (2%)

80. Colon
• The colon extends superiorly from the cecum and consists of the ascending,
transverse, descending, and sigmoid colon
• Ascending & descending segments are retroperitoneal
• Transverse and sigmoid segments are intraperitoneal
1. Ascending colon:-
Extend from cecum to the right lobe of the liver
in 25% of people, has a short mesentery.
12.5 cm length
lies between the left colic flexure and the left iliac fossa.
Has a short mesentery in approximately 33% of people
2. The descending colon

81. 3. Sigmoid colon
• Begins above the pelvic inlet and extends to the level of vertebra S3, where
it is continuous with the rectum
• Is S-shaped structure
• Quitemobile except at its beginning where it continues from the
descending colon, and at its end, where it continues as the rectum
• It is suspended by the sigmoid mesocolon
4. Transverse colon
• Is the third, longest (50cm), and most mobile part of the large intestine
• It crosses the abdomen from the right colicflexureto the left colicflexure.
• Being freely movable, the transverse colon is variable in position, usually hanging
to the level of the umbilicus (L3 vertebral level)

82. Rectum
• Extending from the sigmoid colon is the rectum
• Internally are transverse folds called rectal valves
• Rectal valves separate feces from flatus,
thus allowing gas to pass

83. • The anal canal has two sphincters
• External anal sphincter (skeletal muscle) : Voluntary
• Internal anal sphincter (smooth muscle): Involuntary
• These sphincters which act to open and close the
anus, are ordinarily closed excepts during defecation
Anal canal
• The continuation of the large intestine inferior to the
rectum
• Lies entirely external to the abdominopelvic cavity
• About 3 cm long the canal begins where the rectum
penetrates the muscles of the pelvic floor

86. Accessory Organs of the Digestive System
A)Liver
Is surrounded by the peritoneum
Functions of liver:-
Detoxification
Destruction of spent aged RBCs
Synthesis of bile
Synthesis of plasma proteins, heparin
Metabolic activities

87. Liver: gross anatomy
• Reddish, blood rich & the largest gland in the body
• Weighing about 1.5 kg in the average adult
• Lies mainly in the right upper quadrantof the abdomen deep to
ribs 7-11 on the right side
• Occupies the right hypochondriac and epigastric regions
• Protected by thoracic cage and diaphragm
Relation:-
• Superior: diaphragm
• Left: stomach
• Inferior: transverse colon

89. Liver: gross anatomy
•The liver has four lobes; right, left, caudate and quadrate
•Falciform ligament separates the right and left lobes
anteriorly and suspends the liver from the diaphragm
•Running along the free inferior edge of the
falciform ligament is the ligamentum teres, a
remnant of the fetal umbilical vein

91. Cont.
• Has two surface:-
• Convex diaphragmatic
• Concave visceral
Portal triads include:-
portal vein
hepatic artery
bile duct
from posterior to
anterior

92. Liver receive blood from:-
Hepatic artery (20%) oxygen rich blood
Portal vein (80%) nutrient rich deoxygenated blood some
times toxic nutrient containing blood
Liver cells secrete bile - right and left hepatic ducts-form
common hepatic duct
Common hepatic duct and cystic duct(From gallbladder)-
will form common bile duct
Innervation: Left vagus and sympathetic nerves

94. Gallbladder
•Thin-walled, pear-shaped green muscular sac
•10cm length and 3cm width
•Store andconcentrate bile
•Lies in a shallow fossa on visceral surface of liver
•Expels bile when acidic chyme enters the duodenum or as
a result of cholecystokinin release

95. Blood supply
• Cystic artery a branch
of the right hepatic
artery
• Cystic veins drain into
the portal vein

96. All venous blood from the abdomen drains into the portal vein and
into the liver
The Inferior mesentericvein drains into the Splenicveinwhich joins the Superiormesentericvein to form the Portal
vein

97. The portal venous system
• The portal vein is formed by the union of the splenic vein and the superior
mesenteric vein posterior to the neck of the pancreas at the level of
vertebra L1.
• Blood from the intestine is nutrient rich
• It all drains into the portal vein which flows into the hilum of the liver
• On approaching the liver, the portal vein divides into right and left
branches, which enter the liver

98. • The portal vein then branches
eventually forming the liver sinusoids
that perfuse each liver cell
• After processing by the liver cells, the
blood is collected again in the hepatic
veins which flow into the inferior vena
cava and on to the right atrium
• Other tributaries to the portal vein
include:
• right and left gastric veins
• cysticveins
• Para-umbilical veins
The portal veins

100. Portacaval system (portosystemic anastomosis)
• Connections between portal and systemic venous systems
• The sites of anastomosis are:
• Gastroesophageal junction
• Between esophageal veins draining into the azygos vein
(systemic) and left gastric vein (portal)
• When dilated results in esophageal varices
• Anal canal
• Between rectal veins, the inferior and middle draining into the
inferior vena cava (systemic) and the superior continuing as the
inferior mesenteric vein (portal)
• When dilated, these are hemorrhoids

101. Cont.
Anterior abdominal wall around
the umbilicus
•Paraumbilical veins
(portal) anastomosing with
small epigastric veins of the
anterior abdominal wall
(systemic)
•These may produce the
"caput medusae"

102. Portal hypertension
•If portal vein pressure is very high (e.g. in cirrhosis), the
portal blood cannot all get through the liver
•Back pressure in the portal vein opens up small pre-
existing connections between the portal venous system
and the systemic/caval venous system
•Blood then bypasses the liver through these connections
•Anastomotic veins become engorged, dilated, or varicose;
as a consequence, these veins may rupture

104. B) Pancreas
• Is a soft, lobulated, tadpole-shaped mixed gland
• It extends from the duodenum to the spleen.
• Is retroperitoneal
• lies deep to the greater curvature of stomach and situated in the
posterior abdominal wall
• Mixed gland, contains both exocrine and endocrine
• Exocrine portion secret pancreatic juice
• Endocrine portion (islets of Langerhans) secret hormones
(insulin & glucagon gland)
• Lies epigastric or left upper quadrant region

105. •Parts
• Head
•Expanded part
•Embraced by C-shaped curve of duodenum
• Neck
•Overlies superior mesenteric vessels
• Body
•Main part
• Tail
•Related to hilum of spleen
•Structure
• Highly lobulated
• Invested by thin collagenous capsule which sends septa
between lobules

108. Blood supply and innervation
• Artery
 Pancreatic arteries from splenic
artery
 Pancreaticoduodenal arteries
from hepatic and superior
mesenteric artery
• Vein:
superior mesenteric veins
• Nerves
• From vagus and splanchnic
nerves

109. Spleen
• Lies the left upper quadrant, or left hypochondrium, of the abdomen deep to
rib 9-11.
• Is intraperitoneal purplish color, oval shaped lymphoid organ
• Is the most frequently injured organ in the abdomen.
• Has about 180-250gram weight
Function:-
⇛Provide immune response
⇛Lymphocyte proliferation (B&T cells)
⇛Destruction of aged erythrocytes and platelets
⇛Recycling iron and globin
⇛RBC formation in early fetal life and reservoirs of RBC.