Radiological features of the Heart Dr. Nivin Sharaf MD LMCC

Objectives This lecture will cover the ILO: Delineate the surface, and radiological anatomy of the heart By the end of this lecture we should be able to: Recognize the importance of the surface anatomy of the heart Differentiate between PA and AP views of the heart Recognize the different anatomical structures viewed in the AP/ PA and lateral views of the chest

Surface Anatomy

Surface Anatomy Cont.

Important points to remember Apex: Left 5 th intercostal space, mid clavicular line Aortic Pulmonary Tricuspid Mitral “AParTment M”

Surface Anatomy Cont.

PA View 1. Chest radiograph PA projection In a PA chest film of diagnostic quality the medial ends of the clavicles are equidistant from the spinous process of the adjacent thoracic vertebra. This indicates that it was taken with a truly sagittal X-ray beam. The hemidiaphragm should project at the level of the posterior portion of the tenth rib, or lower. This indicates that the exposure was made during deep inspiration.

PA View Cont. In adults the heart and major vessels attached to it cast almost all of the mediastinal soft-tissue density shadow between the two radiolucent lung fields. (The vertebral column and sternum also contribute to the mediastinal shadow.) The right border of the mediastinum is composed of the following set of structures (listed from superior to inferior): brachiocephalic artery and R. brachiocephalic vein superimposed superior vena cava and aorta superimposed R. atrium inferior vena cava

PA View Cont. The left border of the mediastinum is composed of the following set of structures (also listed from superior to inferior): L. subclavian artery and L. brachiocephalic vein superimposed posterior part of the aortic arch (the aortic knob) pulmonary trunk auricle of the L. atrium (atrial appendage) L. ventricle Even though the diaphragm is one continuous sheet of muscle it radiographs as two distinct hemidiaphragm silhouettes.

Notice the patient is standing!

Positioning

Machine

AP View

Portable X Ray Machine

Lateral View In this view the tracheal lumen appears as an almost vertical radiolucent band which ends just behind the superior aspect of the posterior border of the cardiac shadow. The radiodensities of the two hila are superimposed at the inferior end of the trachea. The radiolucent area bounded by the sternum anteriorly and the cardiac shadow and ascending aorta posteriorly is called the retrosternal area. The radiolucent area directly posterior to the lower part of the cardiac shadow is called the retrocardiac area. As in the PA projection, the diaphragm images as two separate hemidiaphragms in the lateral projection.

References atlas/Thorax/1chestra.html atlas/Thorax/1chestra.html