Aortic arches
Aortic arches | |
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Details | |
Identifiers | |
Latin | arteriae arcuum pharyngeorum |
TE | arches_by_E4.0.3.5.0.3.3 E4.0.3.5.0.3.3 |
Anatomical terminology |
The aortic arches or pharyngeal arch arteries (previously referred to as branchial arches in human embryos) are a series of six paired embryological vascular structures which give rise to the great arteries of the neck and head. They are ventral to the dorsal aorta and arise from the aortic sac.
The aortic arches are formed sequentially within the pharyngeal arches and initially appear symmetrical on both sides of the embryo,[1] but then undergo a significant remodelling to form the final asymmetrical structure of the great arteries.[1][2]
Structure
Arches 1 and 2
The first and second arches disappear early. A remnant of the 1st arch forms part of the maxillary artery,
Note that the external carotid buds from the horns of the aortic sac left behind by the regression of the first two arches.
Arch 3
The third aortic arch constitutes the commencement of the internal carotid artery, and is therefore named the carotid arch. It contributes to the common carotid arteries bilaterally and the proximal portion of the internal carotid arteries bilaterally.[7][6]
Arch 4
Also known as the systemic arch. The fourth right arch forms the most proximal segment of the
Arch 5
The fifth arch either never forms or forms incompletely and then regresses.[2]
Arch 6
The proximal part of the sixth right arch persists as the proximal part of the right pulmonary artery while the distal section degenerates; The sixth left arch gives off the left pulmonary artery and forms the ductus arteriosus; this duct remains pervious during the whole of fetal life, but then closes within the first few days after birth due to increased O2 concentration. Oxygen concentration causes the production of bradykinin which causes the ductus to constrict occluding all flow. Within 1–3 months, the ductus is obliterated and becomes the ligamentum arteriosum.
The ductus arteriosus connects at a junction point that has a low pressure zone (commonly called Bernoulli's principle) created by the inferior curvature (inner radius) of the artery. This low pressure region allows the artery to receive (siphon) the blood flow from the pulmonary artery which is under a higher pressure. However, it is extremely likely that the major force driving flow in this artery is the markedly different arterial pressures in the pulmonary and systemic circulations due to the different arteriolar resistances.
Clinical significance
Most defects of the great arteries arise as a result of persistence of aortic arches that normally should regress or regression of arches that normally should not.
- trachea and esophagus, which may constrict these organs, although usually with no clinical symptoms.
- A double aortic arch; occurs with the development of an abnormal right aortic arch in addition to the left aortic arch, forming a vascular ring around the trachea and esophagus, which usually causes difficulty breathing and swallowing. Occasionally, the entire right dorsal aorta abnormally persists and the left dorsal aorta regresses in which case the right aorta will have to arch across from the esophagus causing difficulty breathing or swallowing.
- Right-sided aortic arch
- Patent ductus arteriosus
- Coarctation of the aorta
Additional images
-
Diagram showing the origins of the main branches of the carotid arteries.
See also
- Pharyngeal arches
References
This article incorporates text in the public domain from page 515 of the 20th edition of Gray's Anatomy (1918)
- ^ PMID 12171473.
- ^ S2CID 7927804.
- ^ a b "Duke Embryology - Craniofacial Development". web.duke.edu. Retrieved 2017-04-10.
- PMID 10730654.
- ^ Sair, Haris. "Persistent stapedial artery | Radiology Reference Article | Radiopaedia.org". radiopaedia.org. Retrieved 2017-04-10.
- ^ PMID 31985966. Retrieved 10 February 2023.
- ^ "Chapter 124. The Aortic Arches - Review of Medical Embryology Book - LifeMap Discovery". discovery.lifemapsc.com. Retrieved 2017-04-10.
- OCLC 1042400100.)
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