What is the Rule of nines in medical terms?

The rule of nines is a method for estimating the total body surface area (BSA) that is burned in a thermal burn injury. It is based on the fact that the human body is divided into 11 regions, each of which represents approximately 9% of the BSA.

The rule of nines is as follows:

- Head and neck: 9%

- Front trunk: 18%

- Back trunk: 18%

- Right upper extremity: 9%

- Left upper extremity: 9%

- Right lower extremity: 18%

- Left lower extremity: 18%

- Genitalia: 1%

- Perineum: 1%

To use the rule of nines, the burned areas are visually estimated and the percentage of BSA involved is calculated for each region. The percentages for each region are then added together to give the total BSA that is burned.

The rule of nines is a simple and quick method for estimating the BSA involved in a burn injury, and it is widely used in emergency medicine. However, it is important to note that the rule of nines is only an estimate and the accuracy may vary depending on the individual patient. In some cases, the use of more precise methods, such as the method of Lund and Browder, may be necessary.