Coarctation of the aorta !

Malformation

A narrowing of the aorta near the ductus arteriosus means the arms get more pressure than the legs.

Updated 2026-11-01

See it in 3D: Aortic arch · Thoracic aorta · Ligamentum arteriosum · Subclavian artery · Left ventricle · Aortic right coronary cusp · Aortic left coronary cusp · Aortic non-coronary cusp

What it is

Coarctation is a narrowing of the aorta, almost always next to the insertion of the ductus or ligamentum arteriosum, distal to the left subclavian. It can be preductal (the severe infant form, duct-dependent) or postductal (the form of older children and adults, with collateral circulation). It is acyanotic, typical of Turner syndrome and associated with a bicuspid aortic valve.

Embryological cause

One theory: ductal smooth muscle extends into the aortic wall and narrows it as the ductus constricts at birth.
Another: an abnormality of the aortic tunica media followed by intimal proliferation.
Reduced flow through the fetal aorta (e.g. with left-sided obstruction) favors a hypoplastic isthmus.
The affected segment lies where the left 4th arch, the ductus (6th arch) and the dorsal aorta meet.

Markers

Turner syndrome (45,X)
Bicuspid aortic valve

How it presents

Infant: heart failure or shock as the ductus closes; absent femoral pulses.
Older child or adult: upper-limb hypertension, headache, leg claudication.
Pressure and pulse difference between arms and legs.
Interscapular systolic murmur; collateral murmurs.

Diagnosis

Measure blood pressure and oximetry in the right arm and one leg.
Echocardiography; CT angiography or MRI define the anatomy.
Chest X-ray: rib notching (in older children) and the '3' sign.

Test yourself

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

Where is coarctation of the aorta almost always located?

Next to the insertion of the ductus or ligamentum arteriosum, distal to the origin of the left subclavian.

Which chromosomal syndrome is associated with coarctation?

Turner syndrome (45,X).

Why does rib notching appear in postductal coarctation?

Intercostal arteries enlarge as collaterals to feed the distal aorta and erode the lower edges of the ribs.

Why does an infant with preductal coarctation worsen after a few days?

Because the lower body depended on the ductus arteriosus, and it closes.

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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: Langman's Medical Embryology, 13th ed., ch. 13: Cardiovascular System (Wolters Kluwer, 2015); Coarctation of the Aorta | Congenital Heart Defects (CHDs) | CDC (Centers for Disease Control and Prevention, 2024).

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Representative model, for educational purposes only.