| Table 2-4 | Korotkoff Sounds |
| Phase | Description | Illustration |
|---|
| Phase I | Characterized by the first appearance of faint, but clear tapping sounds that gradually increase in intensity; the first tapping sound is the systolic pressure. | |
| Phase II | Characterized by muffled or swishing sounds; these sounds may temporarily disappear, especially in hypertensive people; the disappearance of the sound during the latter part of phase I and during phase II is called the auscultatory gap and may cover a range of as much as 40 mm Hg; failing to recognize this gap may cause serious errors of underestimating systolic pressure or overestimating diastolic pressure. | |
| Phase III | Characterized by distinct, loud sounds as the blood flows relatively freely through an increasingly open artery. | |
| Phase IV | Characterized by a distinct, abrupt, muffling sound with a soft, blowing quality; in adults, the onset of this phase is considered the first diastolic pressure. | |
| Phase V | The last sound heard before a period of continuous silence; the pressure at which the last sound is heard is the second diastolic pressure. | |