Systolic pressures in the extremities of man with special reference to the toes

Abstract

Systolic pressures have been studied extensively in the fingers but not in the toes. We measured systolic pressures in the toes, fingers, ankles, and wrists of young normal subjects during body heating and cooling. Systolic end points were determined during deflation of pneumatic cuffs by detecting either the appearance of oxyhemoglobin in the skin using a spectroscope, or the increase in the volume of the part using a strain gauge plethysmograph. Toe and finger pressures were higher during vasoconstriction than during vasodilatation (p < 0.001), whereas the ankle-to-toe and wrist-to-finger gradients were higher during vasodilatation (p < 0.005), These changes in pressures and gradients with change in vasomotor state are probably due to alterations in flow through the arteries of the hand and foot and the associated changes in the utilization of pressure energy. Finger pressures were higher than toe pressures during both vasomotor states (p < 0.025). This was only partly explained by the difference in hydrostatic pressure (toes higher than fingers with respect to heart in supine position). The tendency for gangrene to develop in the toes may be related in part to their lower pressures.