Primitive gut: foregut, midgut and hindgut and their arteries !

Embryonic structure

In week 4 the embryo folds and pinches off part of the yolk sac: that becomes the gut tube, split into three segments, each with its own artery.

Updated 2026-11-01

See it in 3D: Stomach · Jejunum · Sigmoid colon · Celiac trunk · Superior mesenteric artery · Inferior mesenteric artery · Abdominal aorta

What it is

The primitive gut is the endoderm-lined tube that forms when the embryo folds in the fourth week. It is divided into foregut, midgut and hindgut, and each segment is supplied by an unpaired branch of the aorta: the celiac trunk, the superior mesenteric artery and the inferior mesenteric artery. This division explains the blood supply, visceral innervation and referred pain of the whole adult abdomen.

Key facts

Week 4: cephalocaudal and lateral folding brings the dorsal part of the yolk sac into the embryo.
The buccopharyngeal membrane closes the cranial end and the cloacal membrane the caudal end; the buccopharyngeal membrane ruptures near the end of week 4.
The pharynx is the most cranial part of the foregut and is studied with the pharyngeal arches.
A dorsal mesentery suspends the whole tube from the posterior wall; a ventral mesentery exists only at the end of the foregut.

Structure

Inner endoderm: lining epithelium and the cells of the liver, pancreas and glands.
Outer splanchnic mesoderm: smooth muscle, connective tissue of the wall and visceral peritoneum.
Enteric neurons and glia that arrive from the neural crest, mainly from the vagal region.

What it becomes

Foregut: pharynx, esophagus, stomach, proximal duodenum, liver, gallbladder, pancreas and the lining of the airways.
Midgut: distal duodenum, jejunum, ileum, cecum, appendix, ascending colon and the proximal two-thirds of the transverse colon.
Hindgut: distal third of the transverse colon, descending and sigmoid colon, rectum, upper anal canal and the lining of the bladder and urethra (via the cloaca).

The gut tube in three segments

Segment	Artery	Adult organs	Referred pain
Foregut	Celiac trunk	Abdominal esophagus, stomach, duodenum to the papilla, liver, gallbladder, pancreas	Epigastrium
Midgut	Superior mesenteric	Distal duodenum, jejunum, ileum, cecum, appendix, ascending colon, 2/3 of transverse	Periumbilical
Hindgut	Inferior mesenteric	Distal 1/3 of transverse, descending, sigmoid, rectum, upper anal canal	Hypogastrium

Markers

SOX2
PDX1
CDX2
HOX
SHH

Test yourself

Think of the answer, then tap the question to see it.

Which artery supplies the midgut derivatives?

The superior mesenteric artery, which is also the axis around which the midgut loop rotates.

Where does the foregut end and the midgut begin?

In the second part of the duodenum, just distal to where the common bile duct opens at the major papilla.

Which germ layer gives rise to the smooth muscle of the gut wall?

Splanchnic mesoderm; the endoderm forms only the epithelium and glands.

Why is early appendicitis pain felt around the umbilicus?

Because the appendix is a midgut derivative and its visceral pain is referred to the periumbilical region.

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See it in 3D

The structures of Durgical's 3D anatomy where it is found.

Acute appendicitis

← All of embryology

Educational content on embryonic development; not a guide to prenatal diagnosis or to medicines in pregnancy and no substitute for a health professional's advice. No doses are given.

Sources: Embryology, Gastrointestinal (StatPearls Publishing (NCBI Bookshelf), 2023); Embryology, Midgut (StatPearls Publishing (NCBI Bookshelf), 2023); Langman's Medical Embryology, 13th ed., ch. 15: Digestive System (Wolters Kluwer, 2015).

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Representative model, for educational purposes only.