Final answer:
The nurse should document 36% of body surface area in the electronic medical record (EMR).
Step-by-step explanation:
The nurse should document 36% of body surface area in the electronic medical record (EMR).
When assessing burns, healthcare professionals often use the 'rule of nines' to estimate the percentage of body surface area affected. According to the rule of nines, each lower extremity represents 18% of the total body surface area. Therefore, both lower extremities combined would account for 36% (18% + 18%) of the body surface area.