156 FURTHER PULSATILE PHENOMENA. 



beginning of the ventricular contraction ; p, of the radial pulse. A is the curve of 

 the radial artery alone. From these curves, as well as from H and C, it is evident 

 that in this instance 9 vibrations occur between the beginning of the ventricular 

 contraction (in H at 22) until the beginning of the pulse in the radial artery (in C 

 at 13), so that 0* 15 sec. elapses between these two events (1 vibration =0*01613 sec.). 

 In Fig. 69 the difference between the carotid and the posterior tibial pulse = 

 0-137 sec. 



Fig. 69. 



Curves of the carotid and posterior tibial taken simultaneously with Brondgeest's 

 pansphygmograph writing upon a vibrating plate, attached to a tuning-fork. 

 , The arrows indicate the identical moment of time in each curve. 



Pathological. In cases of diminished extensibility of the arteries, e.g., in 

 atheroma (p. 127), the pulse-wave is propagated more rapidly. Local dilatations of 

 the arteries, as in aneurisms, cause a retardation of the wave, and a similar result 

 arises from local constrictions. Relaxation of the walls of the vessels in high 

 fever retards the movement (Hamernjk). 



79. Further Pulsatile Phenomena. 



1. In the mouth and nose, when they are filled with air, and the glottis 

 closed, pulsatile phenomena (due to the arteries in their soft parts), may be found 

 communicating a movement to the contained air. The curves obtained are 

 relatively small, and closely resemble the curve of the carotid. A similar pulse 

 is obtained in the tympanum with intact membrana tympani, and when the 

 eoft parts of the tympanum are congested (Schwartze, Troltsch). 



2. Entoptical Pulse, After violent exercise, an illumination corresponding to 

 each pulse-beat, occurs on a dark optical field. When the optical field is bright, 

 an analogous darkening occurs (Landois). The ophthalmoscope occasionally reveals 

 pulsation of the retinal arteries ( Jager), which becomes marked in insufficiency of 

 the aortic valves (Quincke, O. Becker, Helfreich). 



3. Pulsatile Muscular Contraction. The orbicularis palpebrarum muscle 

 contracts under similar conditions synchronously with the pulse ; and it is perhaps 

 due to the pulse-beat exciting the sensory nerves reflexly. The brothers Weber 

 found that not unfrequently while walking, the step and pulse gradually and in- 

 voluntarily coincide. 



4. When the legs are crossed as one sits in a chair, the leg which is supported 

 is raised with each pulse-beat, and it gives also a second or dicrotic elevation. 



5. If, while a person is quite quiet, the incisor teeth of the lower jaw be made 

 just to touch the upper incisors very lightly, we detect a double beat of the lower 



