Ridges on the fingernails is actually very common, and is often not a cause for concern. Ridges often mean that you have a vitamin B-12 deficiency. Vertical ridges, or ridges that run from the cuticle, down to the tip, are normal and many people have them. Ridges that are horizontal however, and run from side to side on your nails, are not normal, and can indicate some internal organ issues. If you have horizontal ridges, you should speak to your doctor to make sure there isn’t a serious issue going on.