9.2. Other Features of the Lungs

Cardiac Notch and Lingula

Note the presence of the cardiac notch and lingula on the left lung. The cardiac notch is an indentation in the left lung that is caused by the heart projecting slightly to the left. The lingula is the flap that overlies the heart when it sits in the cardiac notch.

Surfaces and Borders

Note the following surfaces and reference points of the lungs:

  • Costal surface
  • Mediastinal surface
  • Base of lung
  • Apex of the lung. This sits 3cm above the first rib.
Note the following borders of the lungs:
  • Inferior border: this separates the base from the costal and mediastinal surfaces.
  • Anterior border and posterior border – separates the costal surface from the mediastinal surface at the front and back.