Which nerve is responsible for referred pain in ear?
**Core Concept**
The **trigeminal nerve** and its branches, along with the **glossopharyngeal**, **vagus**, and **cranial nerves**, are involved in the innervation of the ear. Referred pain in the ear can originate from various structures due to the complex innervation.
**Why the Correct Answer is Right**
The correct answer is related to the **Glossopharyngeal nerve (CN IX)**, which provides sensory innervation to parts of the ear. This nerve is responsible for transmitting pain from the ear, particularly the inner ear, and can refer pain from other areas it innervates, such as the pharynx.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because, while involved in facial sensation, it's not primarily responsible for ear pain.
**Option B:** Incorrect as it is involved in motor functions and some sensory functions but not primarily in referred ear pain.
**Option D:** Incorrect because, although it has a branch that contributes to the innervation of the ear, it's not the primary nerve for referred pain in this context.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that the **Glossopharyngeal nerve** can refer pain to the ear from the pharynx, illustrating the complex nature of head and neck innervation.
**Correct Answer:** D. Glossopharyngeal nerve