Lateral chest X-ray

This type of X-ray allows some areas to be seen better than is possible via a PA film. It also allows three- dimensional localisation of pathology. Some features of a lateral film are described below:

lung fissures on lateral chest X-ray:

• oblique - this passes from the anterior quarter of the diaphragm through the hilum and up to the level of the fourth thoracic vertebral body.
• horizontal - this fissure is between the right upper and middle lobes. It passes anteriorly and horizontally from the level of the hilum.

cardiac outline on lateral chest X-ray:

• cardiac structures that are best visible on lateral chest X-ray are the left atrium and the right ventricle (in contrast to the left ventricle and right atrium that are best viewed on a PA chest film). Left atrial enlargement may be visible as an indentation of the oesophagus on a lateral chest film with barium swallow.
• calcification - intracardiac, aortic and pericardial may be seen