Routine CXR

Routine CXR: is PA known as frontal view with optional lateral view.
Both should exposed in full insp. And patient in upright position.
Films taken in exp. Are difficult to interpret because:
1- hazy lung base.
2- heart shadow increase in size.

CXR approach:
1- trace the diaphragm: the upper surface of diaphragm should be clearly visible from CPA to other, except when heart and diaphragm in contact with diaphragm.
On good insp., the dome of rt. Hemidiaphragm at level of ant. End of 6th rib.
The rt. Hemidiaphragm being up to 2.5 cm higher than the left.
2- check the size and shape of heart.
3- check position of heart and mediastinum: normally trachea lies midway or slightly to right of midpoint between medial end of clavicles.
One third of heart is on rt. Of midline and two thirds to left.
4- looks at mediastinum: the outline of heart and med. Should be clearly seen except where the heart lies in contact with the diaphragm.
The rt. Sup. Med. Border is usually straightly or slightly curved.
Left sup. Med. Border is ill defined above aortic arch.
With increasing age the aorta elongates, lead to unfolding of aorta because aorta fixed at aortic valve and diaphragm, lead to ascending aorta deviate to rt., descending aorta deviate to left.
In young children the normal thymus is often clearly seen, with characteristic sail shape, projecting to rt. Side med.
5- hilar shadows: represent the pulm. Arteries and veins.
Air within major bronchi can be recognizes, but walls not usually visible.
Hilar LNs normally too small to seen.
The left hilum usually slightly higher than rt. Side.