The extraosseous and intraosseous vascularity of the lunate was studied in 35 fresh cadaver limbs. The specimens were injected with latex, debrided by a nondissection technique, and cleared by a modified Spalteholtz method. The extraosseous vascularity was profuse through two to three dorsal and three to four volar vessels feeding dorsal and volar capsular plexuses. One to two nutrient vessels were observed entering the dorsal and volar poles of the Innate from both plexuses. The intraosseous vascularity formed one of three consistent patterns with anastomoses of dorsal and volar vessels in each specimen. The vascular patterns support a theory of compression fracture from repeated trauma as the most likely cause of Kienböck's disease.