Physiotherapy chest x-rays
Establishing basic information
Before launching into analysing the x-ray systematically, it important to establish some basic information regarding the film. This includes:
Name of patient and date of x-ray: Errors can occur with the filing of x-rays or the uploading onto the computer. You need to ensure you are looking at the correct patient and most recent film.
Exposure of the film: This will determine how well you can make out the structures / pathologies. Normal exposure should permit you to see the spinous processes as far as the carina (T5) and the intervertabral disc spaces as far as the diaphragm. If you can see the spinous processes and intervertabral spaces all the way down the film, it is too black and overexposed. If you are unable to see the spinous processes and intervertabral spaces as far as expected the x-ray is too white and underexposed. Think of toast, underdone remains white, where as overdone toast is black!
The silhouette sign: You will only see the outline of one structure if it is next to something of a different density.
Position of the patient: This is important when we come to determining whether structures have been pushed or pulled in relation to their normal position. Rotation can be checked for by looking at the distance between the end of the clavicles and the spinous processes. Ideally there should be an equal distance on the left and right. If one end of the clavicle is further away from the spinous process then the other, the patient is rotated towards the side with the larger gap. Side flexion can be checked by looking at the levels of the clavicle. Ideally the clavicles should be aligned and level left and right.
AP verses PA film: This may affect the size of the heart. Chest x-rays taken from in front of the patient (AP films) tend to make the heart look larger due to the divergence of the beams. In an AP x-ray you can also see the medial boarders of the scapular where as in an x-ray taken from behind the patient (PA film) the medial boarders of the scapular move out of the vision of the lungs fields as the patient stands with their arms out to the side.
