title: The lunula: a magnetic resonance imagining approach to the subnail matrix area.
abstract: High-resolution sagittal magnetic resonance images depict an oval area in the dermis beneath the nail matrix that gives a particular signal. This study defines the magnetic resonance imaging characteristics of this area and examines its correlation with the lunula. A high-resolution surface gradient coil specially designed for skin imagining was used on a 1.5 T magnetic resonance unit. The subnail matrix (SNM) areas of 12 subjects had a significantly longer T2 relaxation time and a higher enhancement ratio after injection of gadolinium than did the nail bed dermis. The length of the SNM area distal to the free edge of the proximal nail fold was highly correlated with the length of the lunula (R = 0.98) in 30 fingers and 10 toes. The total length of the SNM area was somewhat correlated with the nail thickness (R = 0.86) in 30 fingers. The histology and microvascularization of the subungual tissue in 21 fingers showed that this SNM area had specific features: The area was composed of loose connective tissue without bundles, and the reticular and subdermal vascular networks had large regular meshes in this oval area. The lunula is shown to be linked to a well-defined area in the underlying dermis with a specific histology and microvascularization.
authors.affiliation: Department of Skeletal Radiology, Hôpital Cochin, Paris, France.
authors.forename: J L
authors.initials: JL
authors.lastname: Drapé
authors.forename: W
authors.initials: W
authors.lastname: Wolfram-Gabel
authors.forename: I
authors.initials: I
authors.lastname: Idy-Peretti
authors.forename: R
authors.initials: R
authors.lastname: Baran
authors.forename: S
authors.initials: S
authors.lastname: Goettmann
authors.forename: H
authors.initials: H
authors.lastname: Sick
authors.forename: H
authors.initials: H
authors.lastname: Guérin-Surville
authors.forename: J
authors.initials: J
authors.lastname: Bittoun
mesh_terms: D000328:Adult; D006801:Humans; D008279:Magnetic Resonance Imaging; D008833:Microcirculation / Q000033:anatomy & histology; D009262:Nails / Q000033:anatomy & histology* / Q000098:blood supply