NEB Step-1 Review of Abdominal Contents

1. Review of Abdominal
Contents
Prof. Saeed Shafi

2. Learning Outcomes
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3. 3
Quadrants of Abdomen

10. PARACENTESIS OF ABDOMINAL CAVITY

12. 12
Vertical disposition of peritoneum

13. ATTACHMENT OF MESENTERIES

15. EXTRA-EMBRYONIC COELOM
2nd week1st week

16. INTRA-EMBRYONIC COELOM
3rd week

17. INTRA-EMBRYONIC COELOM
Pericardial cavity
Pleural cavity
Peritoneal cavity
IEC
EEC

18. PERICARDIAL CAVITY

19. INTRA-EMBRYONIC COELOM
Heart
Peritoneal
cavity
Pericardial
cavity
Pericardioperitoneal
canal

20. PERITONEAL CAVITY

22. PERICARDIO-PERITONEAL CANALS
Pericardio-
peritoneal
canal
Pericardial cavity

23. PERITONEAL CAVITY
(Liver)

24. PERITONEAL CAVITY
(Umbilicus)

25. PERITONEAL CAVITY
(Hindgut)

26. PLEURO-PERITONIAL MEMBRANES
Pleural cavityBronchial Buds

27. DEVELOPMENT OF STOMACH(W4)

28. ROTATION OF STOMACH

29. ROTATION OF STOMACH

30. W5
LIVER

31. LIVER
W8

32. DEVELOPMENT OF Liver

33. ROTATION OF DUODENUM

34. The Gastro-intestinal Tract

35. • Hollow muscular tube that transports food &
liquid to the stomach
• Extends from pharynx to stomach
• Follows curve of vertebral column
• Pierces diaphragm at level of T10 vertebra
• Covered anteriorly & laterally in abdomen by
peritoneum= retroperitoneal
• Arterial supply
inferior phrenic artery
left gastric artery
• Venous drainage
left gastric vein
OESOPHAGUS

36. PARTS OF STOMACH
Angular notch : along lesser curvature; junction of body & pyloric part
Cardia : around opening of oesophagus
Fundus : dilated superior part - related to left dome of diaphragm
Body : between fundus & pyloric antrum
Pyloric part : has 2 parts - pyloric antrum & pyloric canal

37. Intestinal mucosa bears :
• transverse folds =
plicae circulares
• small projections =
intestinal villi
• both increase surface
area for absorption
• each villus contains a
terminal lymphatic
called a lacteal
PARTS OF SMALL INTESTINE
Extends from pylorus to ileocaecal junction
Includes duodenum, jejenum, ileum
Small intestine plays primary role in digestion & absorption of nutrients

38. FIRST PART OF SMALL INTESTINE : DUODENUM
• Shortest, widest, most fixed part
• Has C-shaped course around head of pancreas
• Begins at pylorus; ends at duodenojejunal
junction
ARTERIAL SUPPLY
• Superior pancreaticoduodenal artery
(coeliac trunk)
• Inferior pancreaticoduodenal artery
(superior mesenteric artery)
VENOUS DRAINAGE
• Follow arteries - drain into portal vein
• Bile & pancreatic ducts enter its posteromedial
wall
• Duodenojejunal flexure : Junction of duodenum
& jejunum

39. • Begins as a pouch inferior to terminal portion of ileum
• Ends at anus
Functions :
1. Reabsorb water, compact feces
2. Absorb vitamins liberated
by bacteria
3. Store fecal material before
defecation
LARGE INTESTINE : FUNCTIONS

40. 3 components viz.
1. CECUM
• Collects, stores chyme
• Ileocecal valve opens into it
2. COLON
• Bears haustra, taeniae coli, epiploic
appendages
• Subdivided into 4 regions
ascending
transverse
descending
sigmoid
• Terminates in anorectal canal
PARTS OF LARGE INTESTINE
3. RECTUM
• Leads to anus
• Muscular sphincters control passage of
fecal material to anus

41. PARTS OF LARGE INTESTINE: CAECUM
• First part of large intestine
• Continuous with ascending
colon
• Lies in iliac fossa
• Does not have a mesentery
• Has vermiform appendix
attached inferior to ileocaecal
junction
• Appendix has short triangular
mesentery = mesoappendix- that
suspends it from mesentery of
terminal ileum

42. PARTS OF LARGE INTESTINE: ASCENDING COLON
• Passes superiorly from caecum on
right side of abdominal cavity to
liver, turns to left as right colic
flexure
• Lies retroperitoneally along side
posterior abdominal wall
• Covered with peritoneum anteriorly
& on its sides
• Separated from anterior abdominal
wall by coils of small intestine &
greater omentum

43. PARTS OF LARGE INTESTINE: TRANSVERSE COLON
• Largest, most mobile part
• Crosses abdomen from right
colic flexure to left colic
flexure - bends inferiorly to
become descending colon

44. PARTS OF LARGE INTESTINE: DESCENDING COLON
Passes retoperitoneally from left
colic flexure into left iliac fossa,
becomes continuous with sigmoid
colon

45. PARTS OF LARGE INTESTINE: SIGMOID COLON
S-shaped loop - variable in length, links descending colon & rectum.
Extends from pelvic brim to 3rd segment of sacrum where it joins rectum

46. ACCESSORY DIGESTIVE ORGANS
• Liver
• Gallbladder
• Pancreas

47. • Hollow muscular
organ
• Stores & concentrates
bile
• Has fundus, body,
neck
GALLBLADDER

48. • Has head, body, tail
• Pancreatic duct
penetrates wall of
duodenum
• Pancreas is an
exocrine & endocrine
organ
PANCREAS
Exocrine functions:
* Secreting H2O
* Secretes ions
* Digestive enzymes into small intestine

52. Portal
circulation

53. Sites of
portosystemic
anastomosis

54. June 2, 2015
DEVELOPMENT OF MIDGUT

55. June 2, 2015
• The umbilicus of a newborn infant failed
to heal normally. It was swollen and
there was a persistent discharge from
the umbilical stump.
• A sinus tract was outlined with radio-
opaque oil during fluoroscopy.
• The tract was resected on the 9th day
after birth and its distal end was found to
terminate in a diverticulum of the ileum.

56. June 2, 2015
• The umbilicus of a newborn infant failed to heal normally. It was swollen and there
was a persistent discharge from the umbillical stump. A sinus tract was outlined
with radiopaque oil during fluoroscopy. The tract was resected on the ninth day
after birth and its distal end was found to terminate in a diverticulum of the ileum.
 What is the embryological basis
of the sinus tract?
 What is the usuall clinical name
given to this type of ileal
diverticulum?
 Is this anomaly common?

57. June 2, 2015
• An infant was born with a light
gray, shiny mass measuring the
size of an orange and
protruding from the umbilical
region at the time of birth.
• The mass was covered by a
thin transparent membrane.

58. June 2, 2015
• A newborn infant had a light gray, shiny mass measuring the size of an orange
and protruding from the umbilical region. The mass was covered by a thin
transparent membrane.
 What is this congential anomaly called?
 What is the origin of the membrane covering
the mass?
 What would be the composition of the
mass?
What is the embryological basis of this
protrusion?

59. Learning Objective
To discuss development of primitive gut and
embryological basis of various congenital anomalies
of midgut

60. SPECIFIC OBJECTIVES
To describe the
– development of Midgut loop
– Derivatives of midgut loop
– rotation and positional changes
– Factors responsible for normal & defective rotation
– Anomalies due to malrotation of midgut loop

61. DERIVATIVES OF
ENDODERM
contributes to develop epithelium and glands of gut.
MESODERM
development of smooth muscles, connectives
tissue, blood vessels, lymphatics and serosa
NEURAL CREST CELLS
parasympathetic ganglia

62. SOURCES OF GUT DEVELOPMENT
Duodenum (distal to bile duct)
Jejunum
Ileum
Cecum
Appendix
Ascending colon
Transverse colon

65. June 2, 2015
DERIVATIVES OF CRANIAL LIMB OF
MIDGUT LOOP
Cranial limb grows rapidly and forms small
intestine, which returns first and occupies
central position in abdomen:
Duodenum (distal to bile duct)
Jejunum
Ileum (proximal to Meckel’s diverticulm)

66. June 2, 2015
DERIVATIVES OF CAUDAL LIMB OF
MIDGUT LOOP
Caudal limb undergoes little change except for cecal
diverticulum formation:
Ileum (distal to Meckel’s diverticulm)
Cecum
Appendix
Ascending colon
Transverse colon

68. Early 6th Week
Midgut rotates 900 counter clock-wise within umbilical cord
during herniation.
Cranial limb becomes Right & caudal limb becomes left

69. 10th Week
Midgut rotates 90+90=1800 counter clock-wise during reduction of hernia
Right limb becomes caudal
Left limb becomes cranial

70. 11th week & Late fetal period
Midgut rotates 90+90=1800 counter clock-wise during
reduction of hernia
Cranial limb becomes Right & caudal limb becomes left

71. Midgut rotates 90+90+90=2700 counter clock-wise during reduction
of hernia

72. June 2, 2015
Fixation of Intestine
• Phyysiological Umbilical Herniation in 6th week
• 900 counter clockwise rotation during
herniation (around axis of SMA)
• Reduction of Midgut herina in 10th week
• 1800 counter clockwise rotation (around axis
of SMA) during reduction of hernia
• Mesentry of small intestine refixed obliquely
• Dorsal mesentry lost for ascending colon

75. June 2, 2015
Development of Cecum & Appendix
6 Week 8
Week
12
Week
At Birth Adu

76. DEVELOPMENT OF MIDGUT
Mix Rotation
Non Rotation
Reverse Rotation
Subhepatic Cecum Internal Hernia Volvulus of Cecu

77. MECKEL’S DIVERTICULUM

80. June 2, 2015
Take Home Message ?
• Midgut loop & its derivatives
• Umbilical Herniation (6W)&reduction(10W)
• 2700 rotation of Midgut loop (around axis of SMA)
• Fate of ventral & dorsal mesentery
• Development of Cecum&Appendix
• Anomalies of midgut loop
– Left sided colon/ mixed rotation/reverse rotation/ Volvulus
– Meckel diverticulum (vitelline cyst, sinus & fistula)
– Congenital Omphalocele / Umbilical Hernia / Gastroschisis
– Stenosis / Duplication of intestine

81. Case 11-3
A female infant was born with a small dimple where
the anus should have been.Examination of the
infant’s vagina revealed meconium and an opening
of a sinus tract in the posterior wall of the
vagina.Radiographic examination using a contrast
medium injected through a tiny catheter inserted
into the opening revealed a fistulous connection with
the lower bowel.
• With which part of the lower bowel would the fistula
probably be connected?
• Name this anaomaly
• What is the embryologic basis of this condition?

82. Objectives
What is Hindgut ?
How cloaca is transformed into urogenital sinus
and anorectal canal?
What is urorectal septum ?
Difference between low and high anal
anomalies?

85. DERIVATIVES OF HINDGUT
•Splenic flexure of colon
•Descending colon
•Sigmoid colon
•Rectum
•Upper 2/3rd anal canal
•Urogenital sinus

86. Anorectal canal

87. DERIVATIVES OF CLOACA
•Cloaca is the distal dilated end of hindgut
•ventrally it is connected to a finger like diverticulum
allantoise
• Partitioning of cloaca (W 5 – 7) by urorectal septum into
• urogenital sinus (anterior)
• anorectal canal (posterior)
•Partitioning of cloacal membrane into
• anal and urogenital membrane
•Partitioning of cloacal sphincter into
• external anal sphincter and urogenital sphincter
•Parineal body is at the site of intersection of anal
membrane and urorectal septum

88. DEVELOPMENT OF ANAL CANAL
•Upper 2/3rd (endodermal) from hindgut
•Lower 1/3rd (ectodermal) from proctodeum
•Junction between these is at the level of
pectinate line / anal valves / anal membrane
•Innervation & blood supply of anal canal

89. DEVELOPMENT OF ANAL CANAL

90. DEVELOPMENT OF ANAL CANAL

91. DEVELOPMENTAL ANOMALIES
Low annorectal anomalies (imperforate anus / ectopic
anus, anal agenesis, Persistent cloaca etc)
High anorectal anomalies (with or without fistulae)
Anal agenesis with perineal fistula
Ano-rectal agenesis with recto-vaginal fistula
Anorectal agenesis with recto-uretheral fistula

96. Take on Message
What is Hindgut ?
How cloaca is transformed into urogenital
sinus and anorectal canal?
What is urorectal septum ?
Difference between low and high anal
anomalies?

97. Portal circulation
Hepatic portal system
• Sites of porto-systemic anastomosis
• Portal hypertension and its causes?
• Surgical interventions for portal hypertension

98. Tributaries of Portal Vein
• Superior Mesenteric Vein
• Splenic vein
• Right Gastric Vein
• Left Gastric Vein
• Prepyloric Vein
• Superior Pancreaticuduodenal Veins
• Cystic Veins (drains into right branch of portal vein)
• Paraumbilical Veins (drains into left branch of portal vein)

99. Portal
circulation

101. Anal
Musosa