NBME 13 Question (thoracentesis location)

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seminoma

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Dullness to percussion at the level of the 7th rib and below on the right. Where is the most appropriate place to insert the catheter?

Above the 5th rib; midscapular line
Above the 5th rib just to the right of the sternum
Above the 7th rib; paravertebral line
Above the 9th rib; midscapular line

All the other answers are "below" a rib, so obviously those are wrong.

I figured 9th rib at the midscapular line was the best option available, but that doesn't seem like a good idea either.

UW says between the 9th and 11 ribs along the paravertebral line (it doesn't talk about the midscapular, or at least not in any questions I've done so far). UW also says that the lower border of the lung is usually two intercostal spaces above the respective border (which is the 12th rib in the paravertebral line), thus the lower border of the lung would be in the 10th intercostal space (between rib 10 and 11) and sticking a needle above the 9th rib would for sure hit the lung.

So wouldn't you still be worried about hitting the lung with a needle above the 9th rib in the scapular line?

Edit: Also any suggestions regarding resources for important anatomical landmarks would be appreciated. I'm really bad at them and only a few are in FA.

Edit2: Actually, based on this: https://academic.amc.edu/martino/gr...al/CASES/Thorax/Pictures/costodiap recess.jpg 9th looks like it might be ok.. but based on the same image UW ("between the 9th and 11th rib in the paravertebral line") seems to be a really bad idea as the lung is definitely present in the 10th interspace.

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as i know needle is inserted through 9th intercostal space in midaxillary line during expiration to avoid inferior border of the lung. also may be inserted above 9th rib
 
as i know needle is inserted through 9th intercostal space in midaxillary line during expiration to avoid inferior border of the lung. also may be inserted above 9th rib

But we're talking midscapular vs paravertebral vs midaxillary here. Different places means different spaces doesn't it?
 
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