LESSON XVII 

 THE HEART (Concluded) 



PERCUSSION AND AUSCULTATION OF THE HUMAN HEART UNDER 

 DIFFERENT CONDITIONS 



1. The Area of Cardiac Dulness. Percuss the region of the heart 

 of the subject, beginning in each case well without the boundaries of 

 this organ, and passing radially toward the sternal articulation of the 

 third rib. Accurately note the point where the deep resonance of the 

 lung passes over into the area of dulness of the heart. Outline the 

 boundaries of the latter with colored chalk. What is its size and posi- 

 tion? How is this area changed by the movements of the lungs on 

 inspiration and expiration? Explain. If abnormalities in' its size are 

 found,' give probable cause. Outline the area of cardiac flatness. 



Annotation. Percussion is usually practised by placing the middle and index- 

 fingers of your left hand flat against the wall of the chest. Tap upon them sharply 

 with the index and middle fingers of your right hand. In tapping, the right hand 

 should be held lose at the wrist, and the second and third phalanges should be flexed 

 upon the first at right angles. 



2. The Rate of the Heart. Determine by auscultation the number 

 of the heart-beats of the subject while he successively assumes the re- 

 cumbent, sitting, and standing position. Tabulate the results and 

 ascertain the differences. Have the subject make forty flexions and 

 extensions of the arms in one minute. Again determine the cardiac 

 rate. Repeat the count after the subject has made thirty deep knee 

 bendings in one minute, and again after a stationary run lasting one- 

 half minute. Arrange your results in the form of a table. 



Determine the heart-rate for one minute. Ask the subject to swal- 

 low. What difference do you note? 



Determine the heart-rate. Ask the subject to concentrate his atten- 

 tion upon his heart. Do you note any difference? Ascertain whether 

 the subject is able to increase his cardiac rate volitionally. 



Annotation. The method of auscultation is conveniently practised by applying 

 the ear to the chest of the subject, preferably in the region between the left nipple 

 and the sternum. The -sounds are loudest in this area. Since we are dealing in the 

 above experiments with the frequency of the heart, you may allow a thin garment 

 to intervene between your ear and the skin of the subject. 



3. The Cardiac Impulse or Apex-beat. Carefully observe the chest 

 in the region of the apex of the heart, i. e., in the fifth intercostal space, 

 and at a distance of about 2 cm. to the right of the left nipple. Note 

 the periodic protrusion of the chest wall. Mark the location of this 



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