Lunule of nail

The lunule of the nail is the visible, whitish, half-moon-shaped area at the proximal end of the nail plate.

It represents the distal portion of the nail matrix, which is the germinative epithelium responsible for producing the nail plate. The lunule extends beyond the proximal nail fold and is the only part of the matrix that can be seen through the nail plate due to its unique histological features and less compact keratinization, which gives it a lighter color compared to the rest of the nail bed.

Histologically, the lunule is characterized by a thicker epithelium and a looser connective tissue stroma with a prominent vascular network, distinguishing it from the nail bed and the rest of the matrix. The shape and size of the lunule can vary between individuals and digits, and it is most prominent on the thumbs. The lunule plays a structural role in defining the free edge of the distal nail plate and is an important anatomical landmark in nail pathology and surgery.