Written by Neumann and Hagenbach, 1858, based on the data of Poiseuille

Therefore:

F is proportional to Perfusion Pressure

F is proportional to 1 / Eta; inversely proportional to Eta.

F is proportional to r⁴

F is proportional 1 / length; inversely proportional to length.

r is most important factor physiologically in determining blood flow

P is second most important.

Applicability to the Eq. assumes:

Rigid conduit

Streamline flow

Newtonian fluid