What can ridges on my finger nails be caused from?

Finger Nail abnormal: Ridges on one's finger nails are often related to smoking. This damage to tissue is a late symptoms of prolonged lung damage and can even be a sign that one is developing emphysema. There are other rare reasons for this. But this is the most common reason i know. If you do not smoke or have never smoked then a good dermatologist may be able to help sort this out for you.

Vertical nail ridges: are often caused by aging. Other causes include anemia, splinter hemorrhages, or conditions like rheumatoid arthritis, trachyonchia or peripheral vascular disease. Horizontal nail ridges (or Beau’s lines) run across nail & might be signs of diabetes, thyroid disease, kidney disease. They may occur in people who had syphilis or muscles or who had chemotherapy. These should be evaluated.