I have a light brown vertical line on my ring finger. my pigment nail is right there in my photo. it extends to the cuticle, no signs of the nail fold

Get checked: This line could be some type of natural pigmentation. However it could be an abnormal pigmentation, hormonal or perhaps a "splinter hemorrhage " associated with more severe diseases. See your Doctor or a dermatologist.

Hard to say.: Longitudinal brown lines on nails, can be due to Addison's disease, melanoma (skin cancer), a non-cancerous mole, or trauma to the nail. See a doc and get checked. See this site: http://www.medscape.org/viewarticle/571916_3