Foregut: esophagus, stomach rotation and duodenum !

Process

The esophagus splits from the trachea, the stomach turns and the duodenum curls into a C: three steps behind several newborn malformations.

Updated 2026-11-01

See it in 3D: Esophagus · Stomach · Duodenum · Lesser omentum · Vagus nerve · Celiac trunk

What it is

The thoracic and abdominal foregut forms the esophagus, the stomach and the first half of the duodenum. The tracheoesophageal septum separates the esophagus from the respiratory diverticulum; the stomach dilates and rotates; the duodenum bends into a C, lies against the posterior wall and passes through a stage with its lumen plugged. Failures of these steps produce tracheoesophageal fistula, duodenal atresia and other exam-favourite malformations.

Key facts

The muscle of the upper esophagus is striated and that of the lower esophagus is smooth; both receive vagal fibres.
The dorsal mesogastrium follows the rotating stomach and forms the greater omentum; the ventral mesogastrium forms the lesser omentum.
The duodenum receives branches of both the celiac trunk and the superior mesenteric artery because it joins the end of the foregut to the start of the midgut.

Step by step

Week 4: the foregut caudal to the pharynx divides into a ventral respiratory tube and the dorsal esophagus.
The esophagus starts short and lengthens as the heart and lungs descend.
Week 4: a spindle-shaped dilation of the foregut marks the future stomach.
The stomach turns 90° clockwise around its longitudinal axis, and its dorsal wall grows faster than the ventral wall.
A second turn around the anteroposterior axis moves the pylorus to the right and upward, and the cardia to the left and downward.
The duodenum forms a C-shaped loop that swings to the right as the stomach rotates and settles against the posterior wall.
In the second month its lumen is plugged by epithelial proliferation and recanalizes shortly afterwards.

Markers

SOX2
NKX2-1

Clinical notes

Failure of the tracheoesophageal septum: esophageal atresia with or without fistula; polyhydramnios and drooling at birth.
Failure of duodenal recanalization: duodenal atresia with the double bubble sign.
Hypertrophy of the pyloric muscle (not a failure of formation): projectile vomiting a few weeks after birth.
An esophagus that stays too short: part of the stomach remains in the chest (congenital hiatal hernia).

Test yourself

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

Why does the left vagus nerve end up on the anterior surface of the stomach?

Because the stomach rotates 90° clockwise around its longitudinal axis, so its original left side becomes anterior.

What structure separates the esophagus from the trachea?

The tracheoesophageal septum, formed by fusion of the tracheoesophageal folds of the foregut.

Which parts of the duodenum become retroperitoneal?

The second, third and fourth parts, when their dorsal mesentery fuses with the posterior wall; the duodenal bulb stays largely intraperitoneal.

Which malformation results from failed recanalization of the duodenum?

Duodenal atresia or stenosis, with early vomiting and the radiographic double bubble sign.

Add to my cards (4)

See it in 3D

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

← 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); Anatomy, Abdomen and Pelvis, Peritoneum (StatPearls Publishing (NCBI Bookshelf), 2023); Langman's Medical Embryology, 13th ed., ch. 15: Digestive System (Wolters Kluwer, 2015).

Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake

Representative model, for educational purposes only.