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

Nail spicules result from incomplete excision of the nail matrix of the fin ger. We report a histological study to delineate the surface anatomy of the nail matrix. Sections were cut longitudinally and transversely in 19 finge rtips. The proximal midline extent of the nail matrix was measured and expr essed as a ratio of the distance from the nail fold to the distal interphal angeal joint, In the lateral sections, the angle subtended between the midl ine vertical and the lateral extent of the nail matrix was measured. The me an ratio of the proximal extent was 0.55 in the midline and the lateral ang ular extent was 66 degrees, The authors recommend that excision of the nail matrix should be rectangular, extending to the midlateral lines and proxim ally to a point three-quarters of the distance from the nail fold to the di stal interphalangeal joint crease.