Which of the given nerve carries taste sensation from anterior two third of tongue?
**Core Concept**
The question is testing the knowledge of the cranial nerves responsible for transmitting taste sensations from different parts of the tongue. The anterior two-thirds of the tongue receive taste fibers from the facial nerve (cranial nerve VII), while the posterior one-third receives taste fibers from the glossopharyngeal nerve (cranial nerve IX).
**Why the Correct Answer is Right**
The facial nerve carries taste fibers from the anterior two-thirds of the tongue through the chorda tympani nerve, which is a branch of the facial nerve. The chorda tympani nerve synapses in the nucleus solitarius of the brainstem and then sends the taste information to the thalamus and eventually to the primary gustatory cortex. This is a crucial pathway for transmitting taste sensations from the anterior part of the tongue.
**Why Each Wrong Option is Incorrect**
* **Option A:** The glossopharyngeal nerve (cranial nerve IX) is responsible for transmitting taste sensations from the posterior one-third of the tongue, not the anterior two-thirds.
* **Option B:** The vagus nerve (cranial nerve X) is involved in various functions, including parasympathetic innervation of the viscera, but it is not primarily responsible for transmitting taste sensations from the tongue.
* **Option D:** The trigeminal nerve (cranial nerve V) is responsible for transmitting sensations of touch, pressure, temperature, and pain from the face, including the tongue, but it does not carry taste fibers.
**Clinical Pearl / High-Yield Fact**
To remember the cranial nerves responsible for taste sensations, use the mnemonic "Face, Tongue, and Throat" for the facial nerve (cranial nerve VII), glossopharyngeal nerve (cranial nerve IX), and vagus nerve (cranial nerve X), respectively.
**Correct Answer:** C. Facial nerve.