Murray's law has been generalized to provide morphometric relationships amo
ng various subtrees as well as between a feeding segment and the subtree it
perfuses. The equivalent resistance of each subtree is empirically determi
ned to be proportional to the cube of a subtree's cumulative arterial lengt
h (L) and inversely proportional to a subtree's arterial volume (V)raised t
o a power of approximately 2.6. This relationship, along with a minimizatio
n of a cost function, and a linearity assumption between flow and cumulativ
e arterial length, provides a power law relationship between V and L. These
results, in conjunction with conservation of energy, yield relationships b
etween the diameter of a segment and the length of its distal subtree. The
relationships were tested based on a complete set of anatomical data of the
coronary arterial trees using two models. The first model, called the trun
cated tree model, is an actual reconstruction of the coronary arterial tree
down to 500 mu m in diameter. The second model, called the symmetric tree
model, satisfies all mean anatomical data down to the capillary vessels. Ou
r results show very good agreement between the theoretical formulation and
the measured anatomical data, which may provide insight into the design of
the coronary arterial tree. Furthermore, the established relationships betw
een the various morphometric parameters of the truncated tree model may pro
vide a basis for assessing the extent of diffuse coronary artery disease.