In the past the descriptions of the usual relationship of the heart and its valves to the chest wall, in the works on anatomy, have been based upon dissections. These have been supplemented in some cases by the insertion of needles in order that the relationship between the surface and the deeper structures might be retained. That this method was not accurate is evidenced by the great variations in the location, for example, of the heart and its valves, as reported by different anatomists.
For example, Gray1 gives the following description of the heart:
The base looks upward, backward and to the right and is separated from the fifth, sixth, seventh and eighth thoracic vertebrae by the pericardium, esophagus, aorta and thoracic duct.
The apex formed by the left ventricle is directed downward, forward and to the left, and is overlapped by the left lung and pleura; it lies