Aortic arch
 

Course

  • Begins behind the 2nd right sternochondral joint in the sternomanubrial plane

  • Arches upwards, backwards and to the left across the left side of the bifurcation of the trachea.

  • Passes behind the left main bronchus to end in the same plane it began, on the left side of the lower border of the body of T4


 

 
Relations
Anteriorly
Posterior

 

  • Thymus

  • Anterior reflections of both pleurae

  • Left brachiocephalic vein

 

  • Cardiac plexus

  • As it passes to the left, the trachea and esophagus are on its right with the right recurrent laryngeal nerve in the groove between them and thoracic duct on the left of the esophagus.

  • On its left are the left phrenic and vagus nerves

  • The left superior intercostals vein crosses the arch deep to the phrenic nerve but superficial to the vagus.

  • Below the arch the pulmonary trunk bifurcates, the superficial cardiac plexus intervening.

  • Ligamentum arteriosum is attached to the lower border. The left recurrent laryngeak nerve hooks behind and to the left of the arch.

  • The arch lies above the left main bronchus
   

Branches of aortic arch

  • Brachiocephalic trunk
  • Left common carotid artery
  • Left subclavian artery

Variations in the branches of the aortic arch

    • Two subclavian and the two common carotid arteries may arise independently from the arch

    • Three or all four of the main arterial branches may arise by a common trunk e.e.g a common trunk for the two common carotids (bicarotid artery) or for the two left arteries or a common trunk for the right subclavian and the two common carotids.

    • The aortic arch may be right sided or even double (left and right sided), A double aortic arch may forma  ring like constriction around the esophagus and trachea, necessitating surgical relief

    • Additional arteries may spring from the aortic arch especially the right or left vertebral artery and less commonly an accessory artery to the thyroid gland, the thyroide ima.