  The atlas of human acupoints and meridians has been utilized in clinical
practice for almost a millennium although the anatomical structures and
functions remain to be clarified. It has recently been reported that a
long-distance interstitial fluid (ISF) circulatory pathway may originate from
the acupoints in the extremities. As observed in living human subjects,
cadavers and animals using magnetic resonance imaging and fluorescent tracers,
the ISF flow pathways include at least 4 types of anatomical structures: the
cutaneous-, perivenous-, periarterial-, and neural-pathways. Unlike the blood
or lymphatic vessels, these ISF flow pathways are composed of highly ordered
and topologically connected interstitial fibrous connective tissues that may
work as guiderails for the ISF to flow actively over long distance under
certain driving forces. Our experimental results demonstrated that most
acupoints in the extremity endings connect with one or more ISF flow pathways
and comprise a complex network of acupoint-ISF-pathways. We also found that
this acupoint-ISF-pathway network can connect to visceral organs or tissues
such as the pericardium and epicardium, even though the topographical geometry
in human extremities does not totally match the meridian lines on the atlas
that is currently used in traditional Chinese medicine. Based on our
experimental data, the following working hypotheses are proposed. A
comprehensive atlas will be constructed to systemically reveal the detailed
anatomical structures of the acupoints-originated ISF circulation. Such an
atlas may shed light on the mysteries shrouding the visceral correlations of
acupoints and meridians, and inaugurate a new frontier for innovative medical
applications.
