Percussion. Borders of relative and absolute cardiac dullness

The heart percussion allows determining its size, shape as well as the size of the vascular band.

Before percussion it is necessary to determine the level of the diaphragm as the changes in the position of the diaphragm influence the location of the heart in the chest and the borders of the heart dullness. With this purpose, the location of the lower border of the right lung (normally in the 6^th intercostal space) is determined along the right medioclavicular line. Percussion is started from the 1^st intercostal space along the intercostal spaces from a clear to dull sound.

After determining the position of the diaphragm the plessimeter finger is shifted one intercostal space upper (or two ribs, in the 4^th intercostal space) placing it parallel to the right border of the heart. Making taps using medium force, the plessimeter finger is moved along the intercostal space to the heart until deadened sound appears. The right border of the heart is noted along the external border of the plessimeter pointing to the clear sound. It is normally in the 4^th intercostal space 1—1.5 cm outer (to the right) the right sternal line. To determine the upper border of the heart the plessimeter finger is placed in the first intercostal space the left parasternal line and is shifted downwards making taps using medium force until a deadened sound appears. The upper border of relative heart dullness is normally located in the 3^rd intercostal space. The left border of the relative dullness is determined in the same intercostal space, where apical pulse is located, usually in the 5^th intercostal space. Percussion is performed in the 5^th intercostal space from the left anterior axillary line towards the sternum. Normally, it is in the 5^th intercostal space 1-2 cm inner the left medioclavicular line and coincides with the apical thrust.

Then the borders of absolute heart dulness (the area of the heart which is not covered with the lungs and adjoins the breastbone) are determined. Light percussion is used for this purpose. The percussion of this area produces a dull sound. To determine the right border of absolute heart dulness after determining the border of relative dulness in the 4^th intercostal space, the plessimeter finger is placed parallel the sternum and then is moved inward until dull sound appears. Normally the right border of absolute heart dullness is noted along the left edge of the breastbone. To determine the upper border of absolute heart dullness, the plessimeter finger is placed in the 3^rd intercostal space parallel the ribs, the percussion is performed downward the intercostal spaces until a dull sound appears. This is normally located in the 4^th intercostal space. To determine the left border of absolute heart dullness percussion is done along the 5^th intercostal space from the border of relative heart dullness until a dull sound appears. This is normally 1—2 cm inner the left border of relative dullness.

Дата добавления: 2015-11-14