Table 1.

Normal caratheristic of nailfold bed.

Capillary Caratheristics	Normal Findings
Morphology	Hairpin or U-shape, with some degree of tortuosity frequent in healthy subjects
Density (nr capillary/mm)	9–13/mm (average 9/mm)
Limb dimensions	6–19 μm (average 11 μm) for afferent limbs8–20 μm (average 12 μm) for efferent limbs
Venous limb to arterial limb diameter ratio	>2:1
Subpapillary venular plexus (SPVP)	Visible, in approximately one third of subjects
Capillary loops	<35 μm
Microhemorrhages	Single hemosiderin store in normal capillaries can be observed in healthy subjects, especially after trauma