As far as I know they can be a sign of calcium deficiency. You can also get white lines under the nails which can be caused by this or by damage (banging, trapping fingers etc...).
In many cases, changes in the appearance of fingernails can be the first sign of an undiagnosed medical problem such as a circulatory problem, respiratory disorder, iron deficiency anemia, or thyroid disease. Such signs as ridges in the fingernails, discolorations, and changes in the contours of the nail base can be important signs of illness. With that in mind, maybe we should be scrutinizing our fingernails more often! Consult your doctor.
The deep *vertical* lines in your fingernails are genetic. If you have *horizontal* ridges in your nails, you should see a doctor.
With that baloney he is really insulting your common sense.
Most ridges on the fingernails are caused by normal aging and are common. Some ridges though might be an indication of an underlying health problem especially if there is a change in color.
blue fingernails
no
Raynauds Disease
Having vertical (longitudinal) ridges on the fingernails refers to the presence of tiny raised lines or ridges that run up and down the length of the nail. Ridges are among the different kinds of nail abnormalities that can develop due to aging, nail injury, or underlying medical conditions.Many people notice an increase in vertical ridges of the fingernails as they age, and this can be a normal development. Aging has been described as the predominant cause of vertical ridges on the fingernails.Onychorrhexis is the medical term used to describe longitudinal ridges on the nails that often accompany brittle nails.
Sucking my dick
Not really. Blue fingernails can be a sign of hypoxia, a lack of oxygen in the blood. This can happen at high altitude such as mountain climbing or flying in a depressurized airplane higher than about 12,000 feet altitude.
Marks on fingernails usually indicate a vitamin deficiency and are not a sign of cancer.
Objective evidence of disease such as a fever is called a/an sign.