Aortic arches

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Aortic arches
Scheme of the aortic arches and their destination.
Profile view of a human embryo estimated at twenty or twenty-one days old.
Details
Identifiers
Latinarteriae arcuum pharyngeorum
TEarches_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,

external carotid artery. On the obliteration of the stapedial artery, this anastomosis enlarges and forms the internal maxillary artery; branches formerly of the stapedial artery are subsequently considered branches of the internal maxillary artery. The common stem of the infraorbital and mandibular branches passes between the two roots of the auriculotemporal nerve and becomes the middle meningeal artery
; the original supraorbital branch of the stapedial is represented by the orbital twigs of the middle meningeal.

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

left subclavian arteries.[8]

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.

lungs
, but that later both pulmonary arteries take origin from the left arch.

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.

Additional images

  • Diagram showing the origins of the main branches of the carotid arteries.
    Diagram showing the origins of the main branches of the carotid arteries.

See also

  • Pharyngeal arches

References

Public domain This article incorporates text in the public domain from page 515 of the 20th edition of Gray's Anatomy (1918)

  1. ^
    PMID 12171473
    .
  2. ^ .
  3. ^ a b "Duke Embryology - Craniofacial Development". web.duke.edu. Retrieved 2017-04-10.
  4. PMID 10730654
    .
  5. ^ Sair, Haris. "Persistent stapedial artery | Radiology Reference Article | Radiopaedia.org". radiopaedia.org. Retrieved 2017-04-10.
  6. ^
    PMID 31985966
    . Retrieved 10 February 2023.
  7. ^ "Chapter 124. The Aortic Arches - Review of Medical Embryology Book - LifeMap Discovery". discovery.lifemapsc.com. Retrieved 2017-04-10.
  8. OCLC 1042400100.{{cite book}}: CS1 maint: location missing publisher (link
    )

External links