middle mediastinum (anatomy)

Last reviewed 01/2018

The middle mediastinum is the region bounded by:

  • anteriorly: the anterior margin of the pericardium
  • posteriorly: the posterior border of the fibrous pericardium
  • superiorly: an arbitrary plane passing horizontally and posteriorly from the manubriosternal joint to the inferior border of the T4 vertebra
  • inferiorly: diaphragm
  • laterally: mediastinal pleura overlying the lungs

The key structures within the middle mediastinum are the:

  • heart
  • great vessels running to and from heart - small sections of:
    • ascending aorta
    • superior vena cava
    • inferior vena cava
    • pulmonary trunk
    • pulmonary veins
  • pericardium surrounding heart
  • lung roots
  • phrenic nerves - the sections overlying the pericardium