Lateral border of nail

The lateral border of the nail is the anatomical region where the lateral edge of the nail plate meets and is bordered by the lateral nail fold, forming a protective groove along each side of the nail unit.

The nail plate is a laminated, keratinized structure that is embedded within the lateral nail grooves, which are formed by the lateral nail folds on each side of the digit. These lateral nail folds are continuous with the proximal nail fold and consist of skin and underlying connective tissue, providing a protective frame for the growing nail plate and separating it from the surrounding periungual soft tissues.

Microscopically, the lateral border is characterized by the close apposition of the lateral nail fold epithelium to the lateral edge of the nail plate, with the underlying dermis and connective tissue anchoring the nail unit to the distal phalanx.

The lateral nail fold also serves as a barrier to external trauma and infection, and its structure is important in surgical approaches to the nail unit.