Spoon nails are typically related with anemia, or an iron deficiency. Should you have this situation, the nail will seem concave both horizontally or vertically. Spoon nails can affect the fingernails or toenails. The little half-moon at the base of your thumb nails (and maybe several of your other nails) https://remingtonbmoey.humor-blog.com/38139866/nail-care-grade-7-ppt-an-overview