- Begins development in the 6th week
- Starts as several mesodermal cells in the Dorsal Mesogastrium
- Dorsal Mesogastrium, due to the splenic presence, becomes divided into the Splenorenal and Gastrosplenic Ligaments.
- Spleen, thus, comes to lie at the left margin of the Lesser Sac
- Original condensations become aggregated into a single organ
- Mesenchymal budding
- Splenic notch may represent a region where there is incomplete fusion
Accessory spleens/splenunculi
- Locations include the hilum, the gastrosplenic ligament, and the pancreatic tail
- Usual location – along the Splenic Vessels or in the Peritoneal Attachments
- Rarely larger than 2cm
- Can also be found in the greater omentum or even down in the pelvis.
- Develops from a mesenchymal condensation from the dorsal mesogastrium during the 5th week of development.