Which of the following pain is not referred to ear?
**Core Concept**
Referred pain occurs when nociceptive stimuli from internal organs or deep tissues are perceived in a different location, often due to shared nerve roots or spinal segments. The ear receives innervation from the trigeminal nerve (cranial nerve V) for the external ear and the facial nerve (cranial nerve VII) for the external auditory meatus, but also receives some innervation from the vagus nerve (cranial nerve X) and the glossopharyngeal nerve (cranial nerve IX) for the middle ear and internal ear.
**Why the Correct Answer is Right**
The ear receives pain referred from the following sources: the temporomandibular joint (TMJ), the auriculotemporal nerve (which supplies the TMJ and receives pain from the dura, sinuses, and teeth), the external ear (supplied by the auriculotemporal nerve and the great auricular nerve), and the external auditory meatus (supplied by the facial nerve). However, pain from the following structures is not referred to the ear:
**Option A:** Trigeminal neuralgia. This condition affects the trigeminal nerve and causes pain in the face, but not typically referred to the ear.
**Option B:** Glossopharyngeal neuralgia. This condition affects the glossopharyngeal nerve and can cause pain in the throat and ear, due to the nerve's overlap with the vagus nerve.
**Option C:** Occipital neuralgia. This condition affects the greater and lesser occipital nerves and can cause pain in the back of the head and ear.
**Option D:** Cervicogenic headache. This condition affects the cervical spine and can cause pain in the head and ear due to the shared nerve roots.
**Clinical Pearl / High-Yield Fact**
The trigeminal nerve is responsible for facial sensation and motor function, but also has a role in the referred pain of the ear, particularly from the TMJ and external ear.
**Correct Answer: A. Trigeminal neuralgia.**