Beau's lines are deep grooved lines that run from side to side on horizontal fingernail or the toenail.
All you need to know about ridges in fingernails
They may look like indentations or ridges in the nail plate. Beau's lines are horizontal, going across the nail, and should not be confused with vertical ridges going from the bottom cuticle of the nail out to the fingertip.
These vertical lines are usually a natural consequence of aging and are harmless.
While Beau's lines are actual ridges and horizontal in the nail plate, Muehrcke lines are areas of hypopigmentation without palpable ridges; they affect the underlying nail bed, and not the nail itself.
Thumb lines should also be distinguished from Mees' lines play bondage games the fingernails, which are areas of discoloration in the nail plate.
There are several causes of Beau's lines. It is believed that ridges is a temporary cessation of cell division in the nail matrix. This may be caused by an infection or problem in the nail fold, where the nail begins to form, or it may be caused by an thumb to that area. Some other reasons for these lines include trauma, coronary occlusionhypocalcaemiaand skin disease. They may be a sign of systemic disease, or may also be caused by an illness of the body, as well as drugs used in chemotherapy ridges malnutrition.