Opening of posterior ethmoid sinus is in:
**Core Concept**
The posterior ethmoid sinus is one of the paranasal sinuses, and its drainage is crucial for the prevention of sinusitis. The **ethmoid bone** contains multiple small air cells, and the posterior ethmoid sinus is located in this bone. Understanding the anatomy of the **paranasal sinuses** is essential for diagnosing and treating sinus diseases.
**Why the Correct Answer is Right**
The correct answer is related to the anatomical location of the posterior ethmoid sinus. The **superior nasal meatus** is the correct location for the opening of the posterior ethmoid sinus, as it allows for the drainage of mucus from the sinus. This is due to the proximity of the posterior ethmoid sinus to the **superior nasal meatus**.
**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect because the **middle nasal meatus** is associated with the opening of the anterior ethmoid sinus and the **frontal sinus**.
**Option B:** This option is incorrect as the **inferior nasal meatus** is associated with the **nasolacrimal duct**.
**Option D:** This is incorrect because the **sphenoethmoidal recess** is associated with the **sphenoid sinus**.
**Clinical Pearl / High-Yield Fact**
It's crucial to remember that the posterior ethmoid sinus opens into the **superior nasal meatus**, which can be a site for infection spread.
**Correct Answer:** C. Superior nasal meatus