Bleeding, technically known as hemorrhaging or hæmorrhaging (see American and British spelling differences), is blood escaping from the circulatory system.^[1] Bleeding can occur internally, where blood leaks from blood vesselsinside the body, or externally, either through a natural opening such as the mouth, nose, ear, urethra, vagina oranus, or through a break in the skin. Hypovolemia is a massive decrease in blood volume, and the complete loss of blood, causing death, is referred to as exsanguination.^[2] Typically, a healthy person can endure a loss of 10–15% of the total blood volume without serious medical difficulties (by comparison, blood donation typically takes 8–10% of the donor's blood volume).^[3]