A toenail, also known as a nail plate or unguis, is one of the structures found on the toes of both human feet and other mammals. It consists of keratin, which provides strength and protection for the toe. The toenails grow from the matrix, located underneath the cuticle, and are made up of several layers including the nail plate itself, the lunula (the white half-moon at the base), the paronychium (the fold of skin surrounding the nail), and the hyponychium (the area that attaches to the underlying tissue). Toenails play an important role in protecting the tips of the toes from injury, as well as providing grip when walking. They also contain small blood vessels which can indicate health issues such as poor nutrition or certain diseases.