<prompt> Rule of nine true is used to denote -Depth of bumsof total body surface areaSeverity of bumsType of bum  <response>: Ans. is b i.e., of total body surface area Extent of burnso The surface area burnt is more important than the degree of bum, in assessing prognosis of a given case. For example, a first degree bum over a wride area is more dangerous than a third degree bum over a limited area. For estimation of bum area, there is rule of 9 Wallaces formulaa In adults surface area is calculated by : -1. 9 for the head and neck.2. 9 for each upper limb.3. 9 for the front of each low-er limb.4. 9 for the back of each lowrer limb.5. 9 for the front of the chest.6. 9 for the back of the chest.7. 9 for the front of the abdomen.8. 9 for the back of the abdomen.9. 1 for the genitalia.b In children the calculation is slightly different which can be tabulated as follows :-Area of bodyIn ChildrenLund and browder chartIn AdultsRule of nine: Wallaces formula 1-4 years5-9 years10-14 yearsAdultHead and Neck1915139Trunk front16161618 Front of chest - abdomenTrunk back16161618 Back of chest abdomenUpper limbs19191918 Right-left upper limbsLower limbs30343536 Frontback of right and left lower limbsGenitals0011 