The surface anatomy of the germinal matrix of the nail bed in the finger.

ABSTRACT

Nail spicules result from incomplete excision of the nail matrix of the finger. We report a histological study to delineate the surface anatomy of the nail matrix. Sections were cut longitudinally and transversely in 19 fingertips. The proximal midline extent of the nail matrix was measured and expressed as a ratio of the distance from the nail fold to the distal interphalangeal joint. In the lateral sections, the angle subtended between the midline vertical and the lateral extent of the nail matrix was measured. The mean ratio of the proximal extent was 0.55 in the midline and the lateral angular extent was 66 degrees. The authors recommend that excision of the nail matrix should be rectangular, extending to the midlateral lines and proximally to a point three-quarters of the distance from the nail fold to the distal interphalangeal joint crease.