[Vascular networks of the periphery of the finger nail]

The vascular networks of the periphery of the nail of the finger are studied on fingers of adults, fetus and newborns, by injecting the vascular system with gelatinous Indian ink. The nail is an avascular horny structure, partially covered with the nail fold. It is lying on a nail bed which prolonges forwards with the hyponychium. Each part of the nail apparatus (nail fold, matricial and unmatricial parts of the nail bed, hyponychium) presents a characteristic network which is tributary of dorsal collaterals arising from the digital palmar vessels and from their arcades. These networks are papillar, pseudopapillar, reticular and subdermical. The morphology and density of these networks vary according to their localisation and are superimposed with the histological variations of the different parts of the nail apparatus. Thus the matricial part of the nail bed shows a poor vascularization. It corresponds to the germinative part of the nail and is responsible of the color of the lunula. The unmatricial part of the nail bed and the hyponychium have dense vascular networks with glomi.