Embryology · Respiratory system, diaphragm and body cavities
Diaphragm: its four components and its innervation !
- Embryonic structure
The diaphragm is built from four pieces that form in the embryo's neck and then move down. That is why the phrenic nerve, from C3 to C5, supplies it.
Updated 2026-11-01
See it in 3D: Diaphragm · Phrenic nerves · Esophagus · Inferior vena cava · Pericardium
What it is
The diaphragm forms from four components: the septum transversum, the pleuroperitoneal membranes, the dorsal mesentery of the esophagus and muscular ingrowth from the body wall. It starts at cervical level and descends as the embryo grows, taking the phrenic nerves from C3 to C5 with it. Incomplete closure causes congenital diaphragmatic hernia.
Structure
- Week 4: the septum transversum, a plate of mesoderm between the heart and the yolk stalk, lies opposite the cervical somites.
- Nerves from segments C3 to C5 grow into the septum: these are the phrenic nerves.
- Week 5: the pleuroperitoneal folds appear and grow to separate the pleural from the peritoneal cavity.
- Muscle cells from the cervical somites migrate into the pleuroperitoneal membranes.
- Week 7: the membranes fuse with the septum transversum and the mesentery of the esophagus.
- Rapid dorsal growth of the embryo carries the diaphragm down to its thoracolumbar level.
What it becomes
- Septum transversum: central tendon of the diaphragm; it also hosts the growing liver and forms the ventral mesentery.
- Pleuroperitoneal membranes: the posterolateral part of the diaphragm.
- Dorsal mesentery of the esophagus: right and left crura.
- Body wall mesoderm: the peripheral muscular rim.
Components of the diaphragm
| Embryonic component | Adult part |
|---|---|
| Septum transversum | Central tendon |
| Pleuroperitoneal membranes | Posterolateral portion (small) |
| Dorsal mesentery of the esophagus | Crura |
| Body wall | Muscular periphery |
Clinical notes
- Referred shoulder pain: irritation of the diaphragm (for example by blood or a subphrenic collection) is felt in the C4 territory.
- Phrenic nerve injury: paralysis and elevation of the hemidiaphragm.
- Bochdalek hernia: failure of the pleuroperitoneal membrane, nearly always on the left.
- Morgagni hernia: anterior parasternal defect, rare.
Test yourself
Think of the answer, then tap the question to see it.
Which embryonic component forms the central tendon of the diaphragm?
The septum transversum.
Why is the diaphragm supplied by cervical roots (C3 to C5)?
Because it forms opposite the cervical somites and then descends as the embryo grows, dragging the phrenic nerves with it.
Which part of the diaphragm comes from the dorsal mesentery of the esophagus?
The crura of the diaphragm.
Why is congenital diaphragmatic hernia more common on the left?
Because the left pericardioperitoneal canal closes after the right, and the left pleuroperitoneal membrane fails more often.
See it in 3D
The structures of Durgical's 3D anatomy where it is found.
Related
- Congenital diaphragmatic hernia
- Intraembryonic coelom: pericardial, pleural and peritoneal cavities
- Paraxial mesoderm and somites: sclerotome, myotome, dermatome
- Embryonic folding: head, tail and lateral folds
- Liver, gallbladder and pancreas
Related conditions
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: Congenital diaphragmatic hernia: MedlinePlus Genetics (MedlinePlus, U.S. National Library of Medicine, 2019); Langman's Medical Embryology, 13th ed., ch. 7: The Gut Tube and the Body Cavities (Wolters Kluwer, 2015).
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Representative model, for educational purposes only.