Scaling properties of the placenta's arterial tree.

The purpose of the present work is to establish a basic knowledge about the scaling properties of the placenta's arterial tree. For this end we have analysed X-ray angiograms of 22 normal arterial trees by box counting. All the investigated arterial trees scale closely according to a power-law over a one decade wide range of scales. Perfectly self-similar fractals, of the same resolution as our representation of the arterial tree, do not follow a power-law more closely. The results support the hypothesis that a mechanism or rule--as regular as those which dictate the structure of perfectly self-similar fractals--also determines fundamental aspects of the arterial tree's morphology.