146 SPHYGMOGRAPHIC TRACINGS FROM DIFFERENT ARTERIES. 



sufficiency, in which, after the contraction of the left ventricle, a large quantity 

 of blood flows back into the ventricle through the leaky semilunar valves of the 

 aorta, and the arteries consequently become relatively bloodless. The pulse-ten- 

 sion is lowest in the standing, higher in the sitting, and highest in the recumbent 

 position. 



Other things being equal, the volume of the pulse-waves may be directly 

 determined from the size of the sphygmographic tracings. Thus, the following 

 types of pulse are distinguished: the large and the small pulse; the unequal pulse; 

 the extremely weak pulse, which is felt only as a succession of faint tremors 

 (tremulous pulse); and the indistinct, scarcely appreciable pulse (filiform and 

 insensible pulse). A large soft pulse is designated a dilated pulse; a small hard 

 pulse a contracted pulse ; a small pulse of great frequency a vermicular pulse ; a 

 large, hard, frequent pulse a serrate pulse; a large, extremely hard pulse a vibrant- 

 pulse ; and a pulse that is different in two corresponding arteries on opposite sides 

 of the body (due to stenosis, compression or kinking on one side) a different pulse. 



SPHYGMOGRAPHIC TRACINGS FROM DIFFERENT ARTERIES. 

 SPHYGMOGRAPHIC CURVE FROM THE CAROTID ARTERY. 



(Fig. 50, I, II, III; Fig. 57, C and C t .) 



The ascending limb is exceedingly steep, the apex of the curve (Fig. 50, 1, P), 

 traced with a minimum degree of friction, being pointed and prominent. The 

 first elevation below the apex is a small one, the valve-closure elevation (Fig. 

 I, K) ; this is due to the positive wave, which is produced during the abrupt 

 closure of the semilunar valves at the root of the aorta and is propagated with 

 but little loss of force into the carotid artery. Close to this elevation and visible 

 only in curves traced with a minimum of friction is the highest elasticity- 

 elevation, which is small (Fig. 50, II, e). Further down, but still above the 

 middle of the descending limb, is the dicrotic elevation (R), which is usually 

 larger and is produced by the recoil of the positive wave from the already closed 

 semilunar valves. Relatively, that is, in comparison with the remaining portions 

 of the curve, the dicrotic elevation is slight, in consequence of the high tension 

 prevailing in the carotid artery. After the dicrotic elevation has been formed, 

 the descending limb falls at first abruptly to about the upper third and from 

 this point, in well-traced curves, the writing lever in its downward movement 

 usually traces two more small elevations, the upper of which is an elasticity- 

 elevation, while the lower, which under favorable conditions appears much larger 

 (Fig. 50, III, Rj) , represents the second dicrotic elevation. We have here a true 

 tricrotism, which is the more readily recorded in the carotid, because that 

 artery is shorter than the arteries of the extremities. 



SPHYGMOGRAPHIC TRACING FROM THE AXILLARY ARTERY. 



(Fig. 50, IV.) 



The ascending limb of the curve is exceedingly steep. Not far from the apex 

 there is a small valve-closure elevation (K) , not unlike that seen in the carotid 

 tracing. Below the middle is found the dicrotic elevation (R), which is fairly 

 high, higher than in the carotid tracing, because in the axillary artery the reduc- 

 tion in arterial tension permits of a greater development of the dicrotic wave. 

 Further down, between the apex of the recoil-elevation and the foot of the curve, 

 two or three smaller elasticity-elevations (e e) are seen. 



SPHYGMOGRAPHIC TRACING FROM THE RADIAL ARTERY. 



(Fig. 47; Fig. 50. V-X; Fig. 57, R and R'.) 



The ascending limb (Fig. 50, V) is of medium height; the ascent is moderately 

 abrupt and suggests the shape of the letter f. The apex (P) is usually well marked. 

 Below the apex there appear, when the tension is considerable, two (V, e e) , when 

 the tension is slight, only one elasticity-elevation (VI, IX, e). There then follows 

 at about the middle of the descending limb the recoil-elevation (R), which is 

 usually well marked. This is the more distinct and the better pronounced the 

 larger the number of factors present that favor the development of the secondary 

 wave. It is smallest when the pulse is small and hard, and the artery is greatly 

 distended (Fig. 50, VII, R) ; larger when the tension is moderate; greatest in the 



