Abstract

In this paper the method for capillary fragility by the use of Sato's petechiometer was examined. Comparative study showed that the infraclavicular area is most proper in view-points of both width and stability in value compared with available areas such as inner sides of the arm. Results would better be represented as a critical pressure: a minimum negative pressure to develop a single petechia rather than as gradings of 0 to ?? corresponding to the number of petechiae developed after a definite negative pressure. Normal critical pressure at the infraclavicular area was 82±34.8 mmHg in average of 10 normal males, and 74±25.4 mmHg in average of 10 normal females. These critical pressures were found not to be correlated with either results of tourniquet test or thrombocyte counts in both normal subjects and patients with hematologic disorders.