Calluses and Corns
Calluses and corns are annoying and potentially painful conditions that form thickened areas in the skin in areas of excessive pressure. The medical term for the thickened skin that forms corns and calluses is hyperkeratosis (plural=hyperkeratoses). A callus refers to a more diffuse, flattened area of thick skin, while a corn is a thick, localized area that usually has a popular, conical or circular shape. Corns, also known as helomas or clavi, sometimes have a dry, waxy, or translucent appearance. A callus is also known as a tyloma.

Corns and calluses occur on parts of the feet and sometimes the fingers. Corns are often painful, even when they are small. Common locations for corns are

on the bottom of the foot (sole or plantar surface), over the metatarsal arch (the "ball" of the foot);
on the outside of the fifth (small or "pinky") toe, where it rubs against the shoe;
between the fourth and fifth toes. Unlike other corns that are firm and flesh-colored, corns between the toes are often whitish and messy; this is sometimes called a "soft corn" (heloma molle), in contrast to the more common "hard corn" (heloma durum) found in other locations.