The proximal nail fold (PNF) covers and protects most of the matrix and the newly formed nail plate. The pocket formed by the PNF is called the proximal nail groove. Its most proximal part is named the culde-sac. The most distal part of the PNF forms an acute angle, giving rise to the cuticle, adhering to the plate, and sealing the proximal groove. Disruption of this seal is responsible for inflammatory and infectious disease of the PNF.