Nail long empty may be trauma, nail fungus and other causes. 1. trauma: when the nails are traumatized, such as smashing, gravity extrusion, etc., it is easy to make the nail bed area is damaged, after the injury of the nail bed below the tissue may appear atrophy, so that the nails and the nail bed separation, which leads to nails appear long empty phenomenon. 2. ringworm of the nail: ringworm of the nail is due to dermatophytes invade the nail plate and nail lesions caused by the nail, when the fungus is infected to the nail bed, there will be a nail plate and nail bed separation phenomenon, so that the nails appear cloudy, thickening, long empty and other manifestations. Nail long empty may also have other causes, it is recommended to go to the hospital in a timely manner to improve the examination, clear cause to give targeted treatment.