Okay, let's tackle this question about Dacrocystorhinostomy. The question is asking where the duct is opened during this procedure. First, I need to recall what Dacrocystorhinostomy (DCR) does. From my studies, DCR is a surgical procedure used to treat nasolacrimal duct obstruction. The goal is to create a new passage for tears to flow from the lacrimal sac directly into the nasal cavity.

So the core concept here is the anatomy of the lacrimal system and the purpose of DCR. The lacrimal system includes the lacrimal glands, ducts, and the nasolacrimal duct. When there's a blockage in the nasolacrimal duct, tears can't drain properly, leading to epiphora (excessive tearing). DCR bypasses the blockage by creating a connection between the lacrimal sac and the nasal cavity.

The correct answer should be where the duct is opened into the nasal cavity. The procedure involves removing a small part of the bone to connect the lacrimal sac to the nasal mucosa. So the duct is opened into the middle meatus of the nose, specifically at the anterior ethmoidal cells, creating a new ostium.

Now, looking at the options, the correct one would be the middle meatus. The other options might be other parts of the nose, like the inferior meatus, superior meatus, or maybe the nasal vestibule. Let's break down each wrong option. The inferior meatus is adjacent to the inferior nasal concha, but DCR doesn't target there. The superior meatus is above the middle, so not the correct site. The nasal vestibule is the anterior part, not where the lacrimal system connects.

Clinical pearls: Remember that DCR is the gold standard for nasolacrimal duct obstruction. The new ostium is in the middle meatus, and it's crucial to avoid damaging the medial canthal tendon during surgery. Also, endoscopic DCR is a modern approach that avoids external incisions.

I need to make sure the explanation is concise, covers all sections, and stays within the character limit. Let me structure each part step by step, making sure each section is clear and addresses the key points without getting too technical but precise enough for a medical exam.

**Core Concept**
Dacrocystorhinostomy (DCR) is a surgical procedure to treat nasolacrimal duct obstruction by creating a direct communication between the lacrimal sac and the nasal cavity. The goal is to restore tear drainage by bypassing the obstructed nasolacrimal duct.

**Why the Correct Answer is Right**
In DCR, the lacrimal sac is opened into the **middle meatus** of the nasal cavity. This is achieved by removing a segment of bone between the lacrimal sac and the middle meatus, allowing tears to drain directly into the nose. The procedure is typically performed at the **anterior ethmoidal cells**, ensuring the new ostium is in the correct anatomical location to avoid obstruction and promote effective tear flow.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect. The inferior meatus is not the target site for DCR; it lies adjacent to the inferior concha and is anatomically too low.
**Option B:** Incorrect. The superior meatus is

✓ Correct Answer: B. Inferior meatus