Classification and measurement of surface microvessels in man

Abstract

Capillary length, width, and number of loops per field have been measured in human surface microvessels. The nailfold was selected as a testing place because of its easy accessibility, the possibility to photograph the loops in all their functional parts, and because of comparative persistency of nailfold capillary patterns. The method of measurement is described and its limitations discussed. Subjects included for study were 37 individuals without clinical disease, 20 patients with systemic lupus erythematosus (SLE), and 25 patients with progressive systemic sclerosis (PSS). The clinical diagnoses had been established independently by the Rheumatic Disease Study Group at the New York University School of Medicine.

The percentage distribution of capillary types found for each group is: normals, 71% within normal limits, 25% tortuous, 2% meandering, 2% general enlargement, and no giant loops; SLE, 21% within normal limits, 44% tortuous, 32% meandering, 3% general enlargement, and no giant loops; PSS, 23% within normal limits, 37% tortuous, 6% meandering, 14% general enlargement, and 20% giant. Measurements of capillary loops in each group have verified preliminary findings of an earlier study, i.e., transitional limb width is greater and the number of capillaries is smaller in PSS than in normals and in SLE. The usefulness of this approach is discussed in terms of possible significance of the findings.