A foreign body completely obstructing the right main bronchus causes –
**Core Concept**
The right main bronchus is more vertical and wider than the left, making it a common site for foreign body obstruction in children. This anatomical feature can lead to a higher likelihood of a foreign body entering the right main bronchus.
**Why the Correct Answer is Right**
When a foreign body completely obstructs the right main bronchus, it can cause significant respiratory distress and potentially life-threatening complications. The obstruction can lead to atelectasis (collapse) of the right lung, which may not be immediately apparent due to the compensatory increase in blood flow to the affected area. However, the right lung's larger size and more vertical bronchus make it more susceptible to complete obstruction.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as the left main bronchus is more horizontal and narrower than the right, making it less likely to be obstructed by a foreign body.
* **Option B:** This option is incorrect as the trachea bifurcates into the right and left main bronchi, but the right main bronchus is not the primary site of bifurcation.
* **Option C:** This option is incorrect as the right upper lobe bronchus is a smaller branch off the right main bronchus and is not a common site for foreign body obstruction.
**Clinical Pearl / High-Yield Fact**
The "right main bronchus is wider and more vertical" is a classic anatomical fact that students should remember when considering potential sites for foreign body obstruction. This knowledge can help in diagnosing and managing patients with respiratory distress.
**Correct Answer:** D