bronchus (right main stem)

Last reviewed 01/2018

The right principal bronchus forms the extrapulmonary division of the trachea that supplies the right lung. It starts at the tracheal bifurcation at the level of the sternal angle. It ends within the parenchyma of the right inferior lobe at the hilum by division into the:

  • middle lobe bronchus
  • inferior lobe bronchus

Proximal to this point, the right superior lobe bronchus arises; it runs laterally to supply the right superior lobe before the hilum of the right lung. This differs from the left side where there is no division of the principal bronchus before the hilum.

The right principal bronchus is shorter than the left side, typically about 4cm in length. It runs more vertically from the tracheal bifurcation, making an angle of only 20-25 degrees with the trachea. Also, it is wider and this makes the right side more susceptible to the entry of foreign bodies which descend the trachea.

The relations of the right principal bronchus include:

  • superiorly: azygous vein arching anteriorly to superior vena cava
  • anteriorly: right pulmonary artery
  • anteroinferiorly: pulmonary veins

The relations of the right principal bronchus are described further in the section on the structure of the right lung root.