A herniated disc may be caused by: 1  Wear and tear of the disc. As you age, your discs dry out and aren't as flexible. 2  Injury to the spine. This may cause tiny tears or cracks in the hard outer layer of the disc.
Definition of wart. 1a : a horny projection on the skin usually of the extremities produced by proliferation of the skin papillae and caused by any of numerous human papillomaviruses âcalled also verruca vulgarisb : any of numerous similar skin lesions not caused by viruses.
A. A wart is a harmless skin growth caused by some types of the virus called the human papillomavirus (HPV) . There are more than 100 known types of HPV. HPV infects the top layer of skin, usually entering the body in an area of broken skin. The virus causes the top layer of skin to grow rapidly, forming a wart.