Final answer:
Using the rule of nines, a patient with burns on the anterior trunk and the entire left arm has an estimated 27% of their total body surface area (TBSA) affected.
Step-by-step explanation:
The rule of nines is used in medical settings to estimate the percentage of the total body surface area (TBSA) affected by burns. In the case of a patient with deep partial-thickness burns of the anterior trunk and the entire left arm, we can calculate the TBSA affected using this method. The anterior trunk (front of the torso) is typically considered as 18% of the total body surface area, and the entire left arm, including the shoulder, as 9%. Therefore, the estimated total percentage of TBSA injured would be the sum of the two areas: 18% (anterior trunk) + 9% (left arm) = 27% TBSA burned.