embryology- development and developmental anomalies of the liver, extrahepatic biliary apparatus, pancreas and spleen. Stages of development of liver, reidel's lobe, annular pancreas. Alimentary tract embryology

1. DEVELOPMENT OF LIVER,
EXTRAHEPATIC BILIARY
APPARATUS, PANCREAS AND
SPLEEN

2. DEVELOPMENT OF LIVER:
The liver develops from an Endodermal hepatic bud that arises from the
ventral aspect of the distal part of the foregut just at its junction with the
midgut in the middle of third week.

3. Formation of Hepatic
bud
Growth of hepatic
bud
Division of Hepatic
bud
Formation of Hepatic sinusoid
Formation of bile canaliculi
Formation of peritoneal ligaments and liver
capsule
Developing liver divides the mesogastrium into
falciform ligament and lesser omentum.
Stages of Development of Liver

4. STAGES OF DEVELOPMENT
1. Formation of Hepatic bud: During the third week of intrauterine life, the
hepatic bud arises from the ventral part of the terminal part of the terminal
part of foregut near junction with the midgut.
2. Growth of the Hepatic Bud: The hepatic bud grows ventrally and cranially in
the ventral mesogastrium and reaches the septum transversum.
3. Division of Hepatic bud : The Hepatic bud divides into cranial pars hepatica
and smaller caudal pars cystica ( forms Gall bladder).The pars hepatica divides
into right and left hepatic ducts . Each hepatic duct forms solid cord of cells
forming interlacing columns called hepatic trabeculae.
4. Formation of hepatic sinusoids : The hepatic trabeculae soon separates from
each other to form hepatic sinusoids. The vitelline and umbilical veins passing
through the septum transversum breakup and establish communication with
hepatic sinusoids

5. cont.
5. Formation of Bile canaliculi: Hepatic ducts branch to form
intrahepatic biliary passages.
6. Formation of peritoneal ligaments and liver capsule : Mesenchyme
of the septum transversum form blood vessels , Kupffers cells ,
haematopoetic cells and capsule of the liver.
7. Developing liver divides the mesogastrium into falciform ligament
and lesser omentum . Reflections of peritoneal covering from liver to
diaphragm forms triangular and coronary ligament.

6. DEVELOPMENT OF LIVER AND GALLBLADDER.

7. CONGENITAL ANOMALIES OF THE LIVER
1. Riedel’s lobe
2. Polycystic disease of the liver.
3. Intrahepatic biliary atresia
4. Caroli’s disease.
5. Rudimentary liver.
6. Absence of quadrate lobe.
7. Presence of accessory liver tissue in the falciform ligament.

8. DEVELOPMENT OF EXTRAHEPATIC BILIARY
APPARATUS
1. Pars cystica gives rise to Gall Bladder
and cystic duct.
2. Two hepatic ducts join to form
Common hepatic duct. Common
hepatic duct cystic duct joins to form
Common bile duct.
3. Differential growth of duodenal wall
changes the opening of common bile
duct from ventral aspect to
dorsomedial aspect of duodenum
along with ventral pancreatic bud.

9. ANOMALIES OF EXTRAHEPATIC BILIARY
APPARATUS
Anomalies of gallbladder:
• Agenesis of gallbladder.
• Sessile gallbladder.
• Phrygian cap.
• Hartmann’s pouch.
• Septate gallbladder.
• Double gallbladder.
• Intra hepatic gallbladder.
• Floating gallbladder.

10. ANOMALIES OF EXTRAHEPATIC BILIARY DUTCS:
(a) Atresia of ducts:
• Atresia of bile duct.
• Atresia of entire extrahepatic biliary duct system.
• Atresia of common hepatic duct.
• Atresia of hepatic ducts.
(b) Accessory ducts :
• Small accessary bile ducts .
• Choledochal cyst(develops due to area of weakness in the wall of the bile
duct and gives rise to obstructive jaundice)
• Moynihan hump( hepatic artery lies in front of the common bile duct
forming a caterpillar like loop).

11. ANOMALIES OF EXTRAHEPATIC BILIARY
APPARATUS

12. DEVELOPMENT OF PANCREAS
1. The pancreas develops from two endodermal pancreatic
buds that arises from junction of foregut and midgut.
2. Due to rotation and differential growth of duodenum the
ventral pancreatic buds shifts from right to left and lies
just below the dorsal pancreatic bud. Both the buds grows
in size and fuses with each other.
3. Dorsal pancreatic bud forms upper part of head, neck,
body and tail of the pancreas .
4. Ventral pancreatic bud forms the lower part of the head
and uncinate process of the pancreas.

13. Derivatives of various parts of pancreas
from dorsal and ventral pancreatic buds

14. Development of Main and accessory
pancreatic ducts
1. Initially dorsal and ventral pancreatic buds have separate
ducts called dorsal and ventral pancreatic ducts that
opens separately into the duodenum. Ventral pancreatic
bud opens in common with the bile duct derived from
hepatic bud.
2. Now communication develops between these two buds .
3. The main pancreatic duct known as duct of wirsung .
4. The proximal part of the dorsal pancreatic duct or duct of
Santorini that opens in the duodenum

15. Formation of annular pancreas

16. Divided pancreas

17. Inversion of pancreatic duct

18. Accessory or ectopic pancreatic tissue
• In this condition small masses or nodules of pancreatic tissues are
located at the following sites:
1. Wall of duodenum
2. Meckel’s diverticulum
3. Gall bladder.
4. Lower end of esophagus.
5. Wall of stomach.

19. Development of Spleen
• Stages of development of spleen
1. Formation of Splenculi
2. Fusion of splenculi
3. Lobulated development of spleen
4. Formation of ligaments
5. Changes in the position of spleen.
6. Haematopoiesis

20. Anomalies of Spleen
1. Accessory spleen in which failure of fusion of splenculi with the main splenic tissue gives rise to accessory
spleen at the following sites:
- Hilus of spleen
- Gastrosplenic ligament
- Lienorenal ligament
- Tail of pancreas
- Along the Splenic artery
- Left spermatic cord
2. Lobulated spleen
3. Hypoplastic spleen or asplenia
4. Polysplenia

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