First part of right subclavian artery (anatomy)

The first part of the right subclavian artery passes from the bifurcation of the right brachiocephalic trunk deep to the right sternocostal joint to the medial edge of the scalenus anterior muscle. In taking this course, it arches over the suprapleural membrane and apex of the lung.

Its relations during this course are:

• anterior:
  • right vagus nerve on its surface
  • cardiac branches of the vagus nerve
  • right common carotid artery proximally
  • ansa subclavia
  • internal jugular vein
  • vertebral vein
  • occasionally, phrenic nerve distally
  • sternothyroid muscle
• posterior:
  • stellate or first thoracic ganglion
  • scalenus minimus
  • suprapleural membrane
  • neck of first rib
• inferior:
  • suprapleural membrane
  • internal thoracic artery
• superior:
  • vertebral artery
  • thyrocervical trunk
  • posteroinferior margin of thyroid lobe

The first part of the right subclavian artery gives off three branches, from proximal to distal:

• vertebral artery; first to arise and passes from the superior margin of the vessel in a superior direction
• thyrocervical trunk; again from the superior surface of the vessel. Passes superiorly.
• right internal thoracic artery; arises from the inferior surface of the subclavian artery just before the medial border of scalenus anterior. Passes inferiorly.