Sensory nerve supply of larynx below the level of vocal card is :
**Core Concept**
The sensory innervation of the larynx below the level of the vocal cords is crucial for protecting the airway and maintaining respiratory function. This region is innervated by sensory nerves that transmit vital information about the larynx's physical state to the central nervous system.
**Why the Correct Answer is Right**
The correct answer is related to the innervation of the larynx by the recurrent laryngeal nerve, which provides sensory innervation below the vocal cords. The recurrent laryngeal nerve is a branch of the vagus nerve (cranial nerve X) that loops around the subclavian artery on the right side and the ligamentum arteriosum on the left side. As it ascends, it provides sensory innervation to the larynx below the level of the vocal cords, including the mucosa of the laryngeal saccule and the ventricles. This innervation is essential for the sensation of pain, temperature, and touch in this region.
**Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not specify the correct nerve or pathway involved in the sensory innervation of the larynx below the vocal cords.
- **Option B:** This option is incorrect because it is not related to the sensory innervation of the larynx; instead, it is associated with motor innervation.
- **Option C:** This option is incorrect because it refers to the superior laryngeal nerve, which provides sensory innervation above the level of the vocal cords.
**Clinical Pearl / High-Yield Fact**
The recurrent laryngeal nerve is vulnerable to injury during thyroid and parathyroid surgery, which can result in vocal cord paralysis and sensory deficits in the larynx below the vocal cords.
**Correct Answer: C. The superior laryngeal nerve supplies above the vocal cords, and the recurrent laryngeal nerve supplies below the vocal cords.**