Aortic arch

The aortic arch represents the direct continuation of the ascending aorta and represents a key area for a review of normal variant anatomy and a wide range of pathological processes that range from congenital anomalies to traumatic injury.

Origin

The aortic arch represents the continuation of the ascending aorta and is nominally defined as starting at the level of the transthoracic plane of Ludwig, a horizontal plane from the sternomanubrial angle to the T4 vertebral body. The sternomanubrial joint is the same level as the second sternocostal articulation.

It courses in a narrow arch from ventral to dorsal and from right to left such that at the end of the arch it sits to the left of midline, adjacent to the thoracic vertebral column.

Branches

Three main branches originate from the upward convexity of the arch in the majority (75%) of patients. In order from proximal to distal the branches are:

  • brachiocephalic trunk or artery (innominate artery) which goes on to divide into the right subclavian and right common carotid arteries
    • the aortic arch can be divided by the brachiocephalic trunk into "proximal" and "distal" portions 3
  • left common carotid artery
  • left subclavian artery
    • just beyond the last branch, the aortic isthmus represents a minor narrowing at the site of the ligamentum arteriosum, which runs between the undersurface of the aortic arch and the terminal pulmonary trunk, this ligament represents the obliterated foetal ductus arteriosus and due to this attachment, this represents the site of the majority of thoracic aortic injuries when the body undergoes significant deceleration
Termination

The arch terminates at the lower border of T4 where it continues as the descending aorta, in the plane of Ludwig, a horizontal plane from the sternomanubrial angle to the T4 vertebral body.

The arch position may be altered:

There are three common variations to the branching pattern of the aortic arch:

  • normal: seen in 75% of patients
  • bovine arch: a common origin of brachiocephalic and left common carotid artery - seen in approximately 15% of patients (more common in individuals of African descent)
  • left common carotid has its origin from the brachiocephalic artery proper, rather than from a common trunk - seen in approximately 10% of patients (also more common in individuals of African descent)

There may be additional branches that arise directly from the arch:

  • thyroidea ima artery, usually between the brachiocephalic and left common carotid
  • left vertebral artery, usually between the left common carotid and the left subclavian arteries
  • rarely the right subclavian and right common carotid arise independently

See: variant anatomy of the aortic arch.

Thoracic anatomy
Share article

Article information

rID: 916
Systems: Vascular, Chest
Section: Anatomy
Tags: aorta, artery, arch
Synonyms or Alternate Spellings:
  • Arch of aorta
  • Aortic arch anatomy

Support Radiopaedia and see fewer ads

Cases and figures

  • Drag
    Figure 1: normal configuration (MRA)
    Drag here to reorder.
  • Drag
    Figure 1: normal configuration
    Drag here to reorder.
  • Drag
    Figure 2: so-called bovine arch
    Drag here to reorder.
  • Drag
    Figure 3: true bovine arch
    Drag here to reorder.
  • Updating… Please wait.
    Loadinganimation

    Alert accept

    Error Unable to process the form. Check for errors and try again.

    Alert accept Thank you for updating your details.