Most of the time the white spots on your nails simply are a sign of a past injury. By the time the white spot shows up (about six weeks after the injury) you've probably forgotten all about banging or knocking your fingers. Sometimes, the injury can stem from a manicure that put excessive pressure on the base of the nails. The white spots also can be a sign of an allergic reaction to nail polish or nail hardeners and, sometimes, are a symptom of a mild infection.
It can also be liver or heart disease, kidney disorders or, more likely, a lack of iron or zinc in your diet.

Ask your doctor about it.

Hi

I think they are 'calcuim' spots .... as nails and bone contain calcuim, any lack of this may cause these spots, and as it starts at the cuticle after a week or 2, as the nail grows, it will eventually get to the tip, it's nothing to worry about, as previously stated by 1nsomni4, you may have knocked it and it's 'fractured'....
Take care

Ginger