Bowel development

Diagram showing the normal process by which the intestine "rotates" and herniates during development

Front intestine

• From the oropharyngeal membrane below the outlet of the liver and pancreas,
• epithelium and glands - endoderm of the yolk sac,
• muscles - ectomesenchym of pharyngeal arches, splanchnic (lateral) mesoderm,
• sublingual and submandibular salivary gland, esophagus, stomach, part of duodenum, liver, gallbladder, pancreas.

Middle intestine

• reaches the Cannon-Boehm point (in the area of flexura lienalis = flexura coli sinistra),
• part of the duodenum, jejunum, ileum, caecum, ascending and most of the transverse colon.

Hind intestine

• Terminated by a cloacal membrane (linea dentata canalis analis),
• descending colon, rectum.

Another structures

Structures attaching the primitive intestine

• Ventral mesogastrium (disappears for middle and hindgut)

-> omentum minus a ligamentum falciforme hepatis - boundaries of the bursa omentalis.

• Dorsal mesogastrium (complete, allow rotation of organs in the peritoneal cavity) -> omentum majus, mesenterium, mesoappendix, mesocolon transversum, mesocolon sigmoideum, Treitz retropancreatic membrane.

Three body cavities

The coelom cavity is gradually divided into:

• pericardial cavity (pericardial),

• pleural cavity,

• peritoneal cavity.