I have two fingernails that have a little dark line on them. Thinking it was really nothing i looked it up ( its called a splinter hemorrhage) and found out that it is caused by either trauma to the nail ( which i dont remember and I have it on 2 nails) or it could mean i have endocarditis an infection of the heart. I am wondering if you guys have ever heard of this or have this on your nails or if i should go to the doctor. I dont know if i am overreacting. thanks.