The nail’s matrix is the tissue under the nail that it rests on, it extends under the nail root, and contains blood vessels and nerves. For just being some tissue under the nail, the matrix is actually responsible for a lot of what makes your toenail, your toenail. The matrix is the location where new cells are produced that will eventually become the nail plate. Even more interesting is that the length, thickness, and overall size of the the matrix will determine the width and thickness of the nail plate above. So provided it is receiving adequate nutrition and is kept in a healthy condition, the nail matrix will continue to grow and keep a healthy nail plate above it. As the previously mentioned cells are created, they push forward the old nail plate cells as they emerge, which is how your nail “grows”. These new cells start out white, but as they push forward more they become translucent, and then appear to be pink as they are “back lit” by the capillaries in the nail bed underneath.