Nail fold

Nail fold is the ridge of skin at the base of the nail plate that frames the nail and holds it in place. It is an important part of the nail unit, which also includes the nail bed, nail matrix, nail plate, and cuticle. The nail fold is often overlooked in discussions of nail anatomy, but it plays a crucial role in nail health and disease.

Anatomy[edit | edit source]

The nail fold is made up of two parts: the proximal nail fold and the lateral nail fold. The proximal nail fold is the portion of the nail fold that is closest to the body, while the lateral nail fold is the portion on the sides of the nail. These folds are made up of epidermal tissue and are covered in skin.

The nail fold serves as a barrier to protect the underlying nail matrix, where new nail cells are produced. It also helps to secure the nail plate in place and prevent it from shifting or becoming dislodged.

Function[edit | edit source]

The primary function of the nail fold is to protect the nail matrix and nail bed from injury and infection. It does this by providing a physical barrier against external threats, such as bacteria, fungi, and physical trauma.

The nail fold also helps to guide the growth of the nail plate. As new nail cells are produced in the nail matrix, they push the existing nail plate forward. The nail fold helps to direct this growth so that the nail grows out straight and smooth.

Health and Disease[edit | edit source]

The health of the nail fold can significantly impact the overall health of the nail. Conditions such as paronychia, a common infection of the nail fold, can cause pain, swelling, and changes in nail growth. Chronic conditions such as psoriasis and lichen planus can also affect the nail fold, leading to changes in nail appearance and function.

In addition to these conditions, the nail fold can also be affected by systemic diseases. For example, changes in the appearance of the nail fold can be a sign of systemic lupus erythematosus, a chronic autoimmune disease.