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...
An injury to a nail may result in the loss of the nail. As long as the nail bed itself wasn't damaged, a lost nail should eventually grow back. Healthy fingernails grow at a rate of about 0.10mm per day, but toenails are slower, growing at only about one half to one third of a fingernail's rate.