Lungs
Each lung is conical in shape, and has
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
Borders
- costal surface
- mediastinal surface
- inferior border
- posterior border
- anterior border
Fissures and Lobes of the Lungs
Hilumleft lung
right 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.
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