PAEA Surgery EOR Exam 2025 – 400 Free Practice Questions to Pass the Exam

The correct answer is the right upper lobe because of the anatomical and structural characteristics of the bronchial tree. In a supine position, gravity affects the distribution of secretions and pathogens within the lungs. The right main bronchus is wider, shorter, and oriented more vertically than the left, making it more susceptible to the entry of aspirated materials, as well as facilitating the spread of infections such as pneumonia.

When a person is stood up or in a natural position, the lung bases are more prone to develop pneumonia due to the tendency for fluid and secretions to pool there. However, in the supine position, aspiration generally leads to involvement of the right upper lobe because when aspirated materials enter the airways, they tend to go into the right mainstem bronchus and subsequently the right upper lobe.

This anatomical predisposition means that pneumonia in the right upper lobe is more frequently encountered in patients who are positioned supine, especially following aspiration events. Therefore, understanding both the positional impact and the anatomical factors leads to recognizing the right upper lobe as the most commonly involved area in pneumonia for patients in this position.