Thin and brittle
Nails which are easily breakable are either a symptom of some genetically caused hormonal disorder or bacterial activity. Thyroid can lead to brittle nails, making them very dry and susceptible to breakage.
Edges on the nail surface
Perfect nails tend to have a smooth surface with no distinct ridges or lines on them. Edges on nails appear when a person is likely to suffer from arthritis or an abnormal condition of lupus when the immunity system of the body attacks its own tissues.
Dunk nails
Such a condition may arise due to a mishap or simply by pushing them too hard. Albeit this, it can also be caused due to a deficiency of zinc content in the body or weak immunity or itchy dry patches around the skin.
Plunging nails
Nails might succumb to hypothyroidism or some innate liver dysfunction like hemochromatosis that leads to bending of nails and a plunge like formation.