cortices. 1  1a (1) : the outer or superficial part of an organ or bodily structure (such as the kidney, adrenal gland, or cerebellum or a bone); especially : cerebral cortex (2) : the proteinaceous usually pigmented layer of a hair below the cuticleb : the outer part of some organisms (such as paramecia)
If a toenail has completely fallen off, it can take up to 18 months for it to grow back. A toenail can take longer to grow back if the nail bed has permanent damage. In some cases, old nails do not completely fall off, and they act as a protective...
Toenails grow about 1 mm per month and take 12-18 months to be completely replaced. Nails grow at different rates due to age, nutrition, and health factors. Under the best of conditions, a nail grows about .004 inches a day or 1/8 of an inch each month. It takes about six months for a new nail to grow from cuticle to tip. The matrix is where the nail forms from; this is what most people call the moon of the nail.