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...
Nail detaches partially or fully from the nail bed: known as onycholysis, it can be caused by a trauma or chemicals as well as certain skin conditions; it will not reattach and you'll need to wait for about six months for a fingernail to grow back fully or 18 months for a toenail.