Which of the following nerve involved in-opening inlet of larynx –
**Core Concept**
The question is testing knowledge of the laryngeal innervation, specifically the nerves involved in controlling the opening and closing of the laryngeal inlet. The correct answer is related to the vagus nerve's branch that innervates the muscles of the larynx.
**Why the Correct Answer is Right**
The correct answer is the recurrent laryngeal nerve, which is a branch of the vagus nerve. The recurrent laryngeal nerve innervates the intrinsic muscles of the larynx, including the posterior cricoarytenoid muscle, which is responsible for opening the glottis (the space between the vocal folds). When the posterior cricoarytenoid muscle contracts, it abducts the vocal folds, increasing the size of the glottis and allowing air to enter the larynx.
**Why Each Wrong Option is Incorrect**
* **Option A:** The superior laryngeal nerve is involved in sensation and motor control of the cricothyroid muscle, but not in opening the laryngeal inlet.
* **Option B:** The internal laryngeal nerve is a branch of the superior laryngeal nerve that provides sensory innervation to the larynx, but it is not involved in motor function.
* **Option C:** The external laryngeal nerve is a branch of the superior laryngeal nerve that innervates the cricothyroid muscle, which is involved in adjusting the tension of the vocal cords, but not in opening the laryngeal inlet.
**Clinical Pearl / High-Yield Fact**
The posterior cricoarytenoid muscle is the only muscle that abducts the vocal folds, and it is innervated by the recurrent laryngeal nerve. This muscle is critical for maintaining a patent airway, and its dysfunction can lead to respiratory difficulties.
**Correct Answer:** A. Recurrent laryngeal nerve.