Black vertical lines on the nail cover are mostly considered to be related to onychomatous nevus, melanoma, trauma and other factors, which belong to skin appendage diseases, so you can hang up with dermatology. Nail nevus is a kind of nevus, its etiology is still unclear, patients are mainly manifested by black vertical channels of uniform width and color on the nail cover; for melanoma patients, black vertical channels may appear on the nails in the early stage, but the local lesion expands rapidly in a short period of time, and for the two cases mentioned above, it is necessary to consult dermatologists. When external force is exerted on the nail cover of the finger, blood vessels may be damaged, and bruises or black vertical paths may appear when there is localized blood stasis, and then orthopaedic consultation is needed. For unexplained finger nail cover inside the black vertical road appears, it is recommended that the patient early to the regular hospital consultation, clear cause of the disease after active treatment.