Pain sensation from ethmoid sinus is carried by
**Core Concept**
Pain sensation from the ethmoid sinus is transmitted through the trigeminal nerve, specifically the ophthalmic division (V1), which is responsible for conveying sensory information from the face and nasal cavity.
**Why the Correct Answer is Right**
The trigeminal nerve has three main divisions: ophthalmic (V1), maxillary (V2), and mandibular (V3). The ophthalmic division (V1) is further divided into three branches: lacrimal, frontal, and nasal. The nasal branch of the ophthalmic division (V1) innervates the nasal cavity and ethmoid sinus, conveying pain and temperature sensations. This is made possible by the presence of nociceptors, specialized sensory receptors that respond to painful stimuli, on the mucosal surfaces of the nasal cavity and ethmoid sinus.
**Why Each Wrong Option is Incorrect**
**Option A:** The maxillary division (V2) primarily innervates the palate, lower eyelid, and the anterior wall of the maxillary sinus, making it an incorrect choice for pain sensation from the ethmoid sinus.
**Option B:** The mandibular division (V3) is responsible for conveying sensory information from the lower face, including the lower lip, chin, and the anterior two-thirds of the tongue, but not from the ethmoid sinus.
**Option C:** The glossopharyngeal nerve (IX) primarily conveys sensory information from the posterior one-third of the tongue and the pharynx, but not from the ethmoid sinus.
**Clinical Pearl / High-Yield Fact**
The trigeminal nerve is a critical structure in the transmission of pain and temperature sensations from the face and nasal cavity. Understanding the innervation patterns of the trigeminal nerve is essential for diagnosing and managing conditions such as sinusitis and facial pain.
**Correct Answer:** C. The mandibular division (V3) is responsible for conveying sensory information from the lower face, including the lower lip, chin, and the anterior two-thirds of the tongue, but not from the ethmoid sinus.