A patient presents with chest pain due to aspiration pneumonitis. On examination there is dullness on percussion in area medial to the medial border of scapula on elevation of arm. Which pa of the lung is most likely to be affected?
First, I remember that percussion dullness indicates consolidation, which is common in pneumonia. The location is key here. The medial border of the scapula, when the arm is raised, probably changes the position of the scapula, making the area more accessible for percussion.
The scapula is on the back, so the lung area medial to it would be the posterior segments. The lower lobe of the lung has a part that's in this area. Specifically, the posterior segment of the lower lobe. Aspiration pneumonitis often affects the lower lobes because of gravity when lying down, but the position here is upright? Wait, when the arm is elevated, the scapula is moved, maybe exposing the posterior lower lobe.
Alternatively, the upper lobe's posterior segment? But upper lobe consolidation might present higher up. The lower lobe posterior segment is more likely when the arm is raised. Let me think about lung anatomy. The right lung has three lobes: upper, middle, lower. The left has upper and lower. The posterior segments of the lower lobes are in the back, medial to the scapula. So the right lower lobe posterior segment would be in that area. But the question doesn't specify left or right, but the answer is likely the right lower lobe posterior segment.
Wait, the question says "area medial to the medial border of scapula on elevation of arm." When the arm is elevated, the scapula moves, but the medial border is near the spine. The area medial to that would be adjacent to the scapula's medial border. The posterior segment of the lower lobe is located in the back, near the scapula. So the most likely answer is the posterior segment of the lower lobe.
Now, the options aren't listed, but based on standard anatomy, the correct answer would be the posterior segment of the lower lobe. The other options might include upper lobe, lateral segment, or other areas. For example, the upper lobe's posterior segment is higher up, not as medial when the arm is raised. The lateral segment is more lateral than the scapula. The anterior segments would be in the front. So the correct answer is the posterior segment of the lower lobe.
**Core Concept**
The question assesses anatomical localization of lung segments based on percussion findings. Aspiration pneumonitis often affects dependent lung regions, and percussion dullness localizes consolidation to specific lobes/segments. The scapular region is anatomically associated with the posterior lower lobe of the lung.
**Why the Correct Answer is Right**
Dullness medial to the medial scapular border on arm elevation suggests consolidation in the **posterior segment of the lower lobe** (e.g., right lower lobe posterior segment). This area is anatomically positioned near the scapula and becomes accessible for percussion when the arm is raised, which displaces the scapula superiorly. Aspiration pneumonitis commonly affects the lower lobes due to gravity-dependent distribution of aspirated material.
**Why Each Wrong