Corns and Callous
A callous is a thickening of the skin over an area of pressure. These are most common over the bony prominences of the feet and hands. When a callous further hardens to form a very localized thickening of skin it is called a corn. Every day walking will create enough pressure over the bony prominences of the feet to cause both corns and callous. Thickening of the skin is the body’s defense against friction and pressure of everyday walking. This prevents the skin from splitting when walking. When the pressure is severe enough a callous (thickened skin) will develop directly over the area where the pressure is applied. When this pressure is applied in the same position for long enough, eventually that skin will thicken more than the surrounding skin causing a very specific type of thickened skin called a corn. When the foot is functioning normally the pressure is distributed relatively evenly across the bottom of the foot.
When there is excess rolling in of the feet the pressure patterns are changed which causes corns and callouses to develop. Corns and callouses usually develop over the bony prominences of the feet due to the increased pressure at these locations. When supporting the body weight in walking and running the pressure on these areas increases dramatically as the skin is effectively pinched between the bones of the foot and the ground. This triggers a protective thickening of the skin. A common misconception is that corns are living tissue and have roots. Corns are actually nothing but dead skin. Callouses are a thickening of a section of the skin (stratum cornium) in response to mechanical pressure. The skin thickens in response to this pressure in order to protect itself from splitting. You will find callouses in most areas where there is increased pressure on the skin, such as the heels and the balls of the feet. These are common areas for callouses to develop. A corn will feel like there is a stone in your shoes. This will usually get worse over time.
Treatment of corns and callous is quite simple. The callous is shaved down and the hard core (the corn) is removed.