ABSTRACT
The matrix is the sole structure to form nail plate keratin. A ngernail grows roughly three times faster than a toenail, with the nail of the dominant middle nger growing fastest with about 3-4 mm per month (Figure 29.6). The big toenail takes approximately 18 months to fully grow out. However, after nail avulsion, the nail growth rate is slightly faster. It is also faster during the warm summer period and due to physical activity and certain drugs, such as azole antifungals and some retinoids; it grows slower during winter, in high altitude, in physically inactive subjects, and under cytotoxic chemotherapy.
