Aortic arches

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  Diagram of the aortic arches in a human embryo.
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  Illustration showing the development of the aortic arches.
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  Aortic arches in a human embryo, lateral view.

Aortic Arches

The aortic arches are a series of six paired embryological vascular structures that give rise to several major arteries in the adult. These arches are crucial in the development of the circulatory system in vertebrates, including humans. They are also known as pharyngeal arch arteries because they are associated with the pharyngeal arches.

Development

The aortic arches develop from the aortic sac, which is an extension of the truncus arteriosus. During embryogenesis, these arches form between the ventral and dorsal aortae and are initially symmetrical. However, as development progresses, they undergo significant remodeling to form the asymmetric arterial system seen in adults.

First Aortic Arch

The first aortic arch largely regresses, but it contributes to the formation of the maxillary artery, which supplies the deep structures of the face.

Second Aortic Arch

The second aortic arch also regresses significantly, with remnants forming the stapedial artery in the embryo, which typically regresses in humans.

Third Aortic Arch

The third aortic arch is crucial as it forms the common carotid arteries and the proximal portion of the internal carotid arteries.

Fourth Aortic Arch

The fourth aortic arch has different fates on the left and right sides. On the left, it forms part of the aortic arch itself, while on the right, it contributes to the formation of the right subclavian artery.

Fifth Aortic Arch

The fifth aortic arch is often absent or rudimentary in humans and does not contribute significantly to the adult arterial system.

Sixth Aortic Arch

The sixth aortic arch is also known as the pulmonary arch. It gives rise to the pulmonary arteries and the ductus arteriosus, which connects the pulmonary trunk to the aortic arch in the fetus. The ductus arteriosus typically closes after birth to become the ligamentum arteriosum.

Clinical Significance

Abnormal development of the aortic arches can lead to congenital vascular anomalies. These include conditions such as coarctation of the aorta, interrupted aortic arch, and various forms of vascular rings that can compress the trachea or esophagus.

Related Pages

• Pharyngeal arches
• Embryology
• Circulatory system
• Congenital heart defect