Lateral fold

The lateral nail fold is the skin and subcutaneous tissue that borders each side of the nail plate, forming a protective frame for the nail as it grows distally.

It consists of an epidermal surface continuous with the dorsal digital skin, underlain by a specialized dermis and subcutaneous tissue. The lateral nail fold is structurally similar to the proximal nail fold, but is located along the lateral margins of the nail plate, creating a groove (the lateral nail groove) in which the nail plate is embedded. The ventral surface of the lateral nail fold is closely apposed to the lateral edge of the nail plate, helping to seal and protect the nail apparatus from external trauma and infection.

The lateral nail fold contains a rich vascular and neural supply, and its connective tissue is anchored to the underlying periosteum and interosseous ligament, providing stability to the nail unit.

Pathologically, hypertrophy or inflammation of the lateral nail fold can result in conditions such as ingrown nails or paronychia.