Paralysis of recurrent laryngeal nerve true is –
**Core Concept**
The recurrent laryngeal nerve (RLN) is a branch of the vagus nerve that supplies motor innervation to the intrinsic muscles of the larynx, except for the cricothyroid muscle, which is innervated by the external branch of the superior laryngeal nerve. The RLN is responsible for controlling the opening and closing of the glottis, thereby regulating the voice and airway patency.
**Why the Correct Answer is Right**
Paralysis of the RLN results in vocal cord immobility, leading to a hoarse voice and difficulty breathing. The affected vocal cord may be paralyzed in an abnormal position, such as the paramedian or posterosuperior position, which can impede airway patency. This is because the paralyzed vocal cord cannot abduct or adduct properly, causing the glottis to be narrowed or closed.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because paralysis of the RLN does not affect the external branch of the superior laryngeal nerve, which innervates the cricothyroid muscle.
* **Option B:** This option is incorrect because paralysis of the RLN does not affect the vagus nerve's parasympathetic innervation to the larynx, which is responsible for regulating mucous secretion and vasodilation.
* **Option C:** This option is incorrect because paralysis of the RLN does not affect the hypoglossal nerve, which innervates the muscles of the tongue.
**Clinical Pearl / High-Yield Fact**
The RLN is at risk during thyroid and parathyroid surgery, and its injury can lead to vocal cord paralysis. It is essential to identify and preserve the RLN during these procedures to prevent long-term voice and breathing difficulties.
**Correct Answer:** Not available, please provide the options.