They're right at your fingertips, but how often do you consider the microscopic anatomy of your fingernails? How is their form fitted to function? Primates, including humans, use fingernails to maintain the anatomic integrity at the distal end of our phalanges, which often serves as the leading edge of our physical sensory apparatus. The nails serve as a stiff backing to the soft pads of our fingers, helping to improve the grip and sensitivity by allowing the pad to “push back” on the object we are touching. Nails also serve specific functions in maneuvering within cracks, scratching, and fighting.

The gross structure of nails helps to resist upward bending forces that are encountered in these functions. The convex curvature contributes, just like a curved piece of paper has more stiffness than a flat sheet. The composition of nails is also suitable. As with the outer layer of skin, and the structure of hair, nails are also composed of keratin.