This
is the commonest radiogram taken and thus it is important that the normal
anatomy is known thoroughly. As with any x-ray, a system must be devised so
that all the film is looked at in turn. However, certain hidden areas on a
chest film warrant special attention and these include: behind the first ribs,
behind the heart shadow, the posterior costophrenic angles which are
obliterated on this view by the diaphragmatic shadows, and the hilar regions.
Note the air in the trachea and main extra-pulmonary bronchi. Note that the
hilar shadows are composed only of vessels and the normal intra-pulmonary
bronchi cannot be visualized. The right heart border is formed from the
superior vena cava, right atrium and inferior vena cava. The left heart border
is formed from the aortic knuckle, the pulmonary conus, the left atrial
appendage and the left ventricle.
