Mesentry Development

Dr Iram Iqbal

Mesentry is a double layer of peritoneum that enclose an organ and

connect it to the body wall

Provide pathways for vessels, nerves and lymphatics

Parts of developing GIT

• Pharyngeal gut• Fore gut• Mid gut• Hind gut

Mesentery Development

• During embryonic development digestive tract and accessory organs are suspended in peritoneal cavity by:

dorsal mesentery ventral mesentery

THE DORSAL MESENTERY

• Extends from lower end of esophagus to the cloacal region of the hind gut

• Derived from splanchnic mesoderm

• In region of stomach- The dorsal mesogastrium or greater omentum

• Duodenum-The dorsal mesoduodenum

• Jejunum & ileum- mesentery proper

• Colon- The dorsal mesocolon

Ventral mesentery

Mesenteries of the Stomach

Primitive Dorsal Mesogastrium

Appearance of the Omental Bursa

Development of Spleen

Elongation of the Dorsal mesogastrium and expansion of the Omental bursa

Formation of Greater Omentum

Mesentry of duodenum

Rotation of stomach causes C shaped duodenum and it rotates to the left.

Duodenum and pancreas become retroperitoneal, Except for Duodenal Cap.

Mesentry of Liver

Mesentry of Pancreas

Mesentries of mid gut

• Rotation of intestinal loop cause twist in dorsal mesentry.

• Ascending colon becomes Retro perotoneal.

• Transverse Mesocolon fuses with posterior wall of Greater Omentum

Mesentry of Hindgut

• Dorsal Mesentry forms Sigmoid Mesocolon.

• Rectum is only partially covered by the peritoneum.

Mesenteries of Digestive Organs

References

1. Langman’s Medical Embryology, 10th edition.

2. Moore Persaud, The Developing Human, Clinically Oriented Embryology, 8th edition.

3. Google search for images