Final answer:
A PA chest x-ray should show the lungs, heart, diaphragm, rib cage, as well as any artificial devices like pacemakers. The pleural and pericardial cavities are also visible, and abnormalities such as lesions can be identified.
Step-by-step explanation:
A PA chest x-ray, or posteroanterior chest x-ray, is an imaging technique that captures detailed pictures of the chest. In a PA chest x-ray, several structures should be visible. These typically include the lungs, with the left and right lung fields showing the lung parenchyma, heart and mediastinal outline indicating the space in the chest that contains the heart, trachea, esophagus, and other structures.
Also visible are the diaphragm, which separates the thoracic cavity from the abdominal cavity, and the rib cage structure. Additionally, any artificial devices such as pacemakers, artificial heart valves, or wires used to close the sternum, should be visible if present.
Another key aspect is the presence of the pleural cavities that house the lungs and the pericardial cavity within the mediastinum that encloses the heart. X-rays can also show abnormal findings like pneumonia, which would present as opaque patches indicating consolidations (lesions).