The damage that is caused when pressure develops can be termed as pressure ulcers, previously termed decubitus ulcers, are also commonly referred to as pressure sores and bed sores. Pressure sores are the result of a constant deficiency of blood to a localized area that creates damage to the skin and underlying tissue as a result of compression between a bony prominence and an external surface. Damage to the skin to create a pressure sore may be caused by forces of pressure, shear and friction acting individually or in combination with each other. The changes the occur when damage caused by pressure develops are as follows; the skin will become discoloured in a partial area – people with pale skin will tend to get red patches, while people with darker skin will tend to get blue or purple patches, these discoloured areas when pressed won’t turn white. The area of skin tends to feel warm, spongy or hard. The individual with the pressure sore will feel pain or itchiness in the affected area. As the pressure sore develops further an open wound may form in the shape of a blister this would be classed as a stage two pressure sore. The wound could develop further and become a deeper wound which reaches into the deeper layers of the skin known as a stage three pressure sore. The wound could even go so deep it may reach the individuals bone and muscle known as a stage four pressure sore.