Lungs

Each lung is conical in shape, and has

• apex
• base
• three borders
• two surfaces

Apex

• rounded
• extends 2.5 to 4 cm into the root of the neck

Base

•  broad and concave
•  rests upon the convex surface of the diaphragm

 Surfaces

• costal surface
• mediastinal surface

Borders

• inferior border
• posterior border
• anterior border

Fissures and Lobes of the Lungs

left lung

• Fissure
  • Oblique fissure, which extends from the costal to the mediastinal surface of the lung both above and below the hilus, devides left lung into upper and lower lobes.
• Lobes
  • upper lobe
    • lies above and in front of this fissure, and includes the apex, the anterior border, and a considerable part of the costal surface and the greater part of the mediastinal surface of the lung.
  • lower lobe
    • the larger of the two, is situated below and behind the fissure, and comprises almost the whole of the base, a large portion of the costal surface, and the greater part of the posterior border.

right lung

Fissures

• Oblique fissure separates lower lobe from upper and middle lobe
  • Right oblique fissure is more vertical than left.
• Transverse fissure separates middle lobe from upper lobe.
  • Transeverse fissure begins in the oblique fissure near the posterior border of the lung, and, running horizontally forward, cuts the anterior border on a level with the sternal end of the fourth costal cartilage; on the mediastinal surface it may be traced backward to the hilus.

Lobes

• Upper lobe
• Middle lobe
• Lower lobe

• by which the lung is connected to the heart and the trachea.
• The structures composing the root of each lung are arranged similarly
  • the upper two pulmonary veins in front
  • the pulmonary artery in the middle
  • the bronchus and the bronchial vessels posteriorly.
• Relationship
  • The root of the right lung
    •  lies behind the superior vena cava and part of the right atrium
    • below the azygos vein.
  • The left lung root
    •  passes beneath the aortic arch and in front of the descending aorta
  • pulmonary ligament is below on both sides