Diogenes of Apollonia: a pioneer in vascular anatomy.

Diogenes of Apollonia was a pre-Socratic philosopher who lived in the 5th century BC and provided the first systematic and fairly truthful account of blood vessel architecture in man. This article presents Diogenes' report and comments on the most significant passages of his vascular description. It also discusses the magnitude of Diogenes' contribution to shape early theories regarding blood vessel physiology. What emerges from this portrait is the figure of an eclectic spirit, who remarkably influenced the development of leading concepts in vascular anatomy and biology.