PURPOSE: � The concept of angiosomes has been monumental to the furthering of reconstructive surgery.� Such detailed, 3-dimensional knowledge of soft tissue vascularity has helped shape reconstruction of nearly every part of the human body.� The advent of perforator-based flaps has created a new degree of freedom to reconstructive design.� Whereas named vessels supply angiosomes, these perforators supply what may be called microangiosomes.  In search of a consistent source of reliable cutaneous perforators, we have discovered some commonalities. 
METHOD:   Corroborated by our literature’s description of various individual perforator flaps, we present here a case series designed to further three hypotheses: 1) There are reliable perforators both proximal and distal to all extremity joints; 2) In general, the direction of blood flow within these microangiosomes extends away from the joint; 3) Predictions of flap size can be anticipated depending on the location of adjacent perforators (and by definition, adjacent microangiosomes).
RESULTS:   Each microangiosome has a self-contained circulation with reliable arterial flow and venous drainage. Many flaps previously considered “distally based” are actually proximally based (from a blood flow perspective), although the base of the pedicle may be distal on the extremity. 
CONCLUSION:   A new concept of microangiosomes has been developed by combining the principles and knowledge of macroangiosomes and perforator flaps. Using this microangiosome concept, free style pedicled and free perforator flaps can be reliably designed and transferred for a variety of defects. Further defining the soft tissue extent of perforator-based microangiosomes will greatly broaden the spectrum of reconstructive surgery.