Structural details of the lungs

Surface markings

The apex:

• Sternoclavicular joint
  
  
• 2.5cm superior to the middle third of the clavicle
  
  
• Junction of the middle and medial thirds of the clavicle.

The anterior border; varies between left and right.

Right side

• Between the levels of the 2 nd and 4 th cartilages anterior margin is near the midline.
  
  
• Inferior to the 4 th costal cartilage, the surface of the right lung gradually diverges from the midline, and leaves the sternum posterior to the 6 th costal cartilage.

Left side

• Close to the midline fill the level of the 4 th costal cartilage the lung deviates laterally to a pint about 2.5cm lateral to the left border of the sternum to form the cardiac notch.
• It then turns inferiorly and slightly medially to the 6 th cartilage.

The inferior border

• Indicated by a line drawn from the inferior end of the line representing the anterior border that crosses :
  
  - the 6 th rib in the midclavicular line;
  - the 8 th rib in the mid-axillary line,
  - the 10 th rib in the midscapular line, and ends about 2.5cm lateral to the spinous process of the 10 th thoracic vertebra.
  
  

• The projection of the oblique fissure is the same for each lung, and is indicated on the surface of the thorax by a line from the spinous process of T2 around the thorax to the 6 th costochondral junction.

• The horizontal fissure (on the right lung) is indicated by a line on the surface of the thorax that runs from the anterior border of the lung along the fourth cartilage to the oblique fissure.