A corn or clavus is an often painful, cone-shaped, inwardly directed callus of dead skin that forms at a pressure point near a bone, or on a weight-bearing part of the body. When on the feet, corns can be so painful as to interfere with walking. The visible portion of the corn tends to be more or less round, but corns are defined by having a hard tapering root that is directed inward, and pressure on the corn pushes this root deeper into the flesh. Pressure corns usually occur on thin or glabrous skin surfaces, especially on the dorsal surface of toes or fingers, but corns triggered by an acute injury may occur on the thicker skin of the palms or bottom of the feet.