In Bilateral palsy of recurrent larygeal nerve there is
## **Core Concept**
Bilateral recurrent laryngeal nerve palsy involves the paralysis of both recurrent laryngeal nerves, which are branches of the vagus nerve (cranial nerve X) that supply the intrinsic muscles of the larynx, except for the cricothyroid muscle. This condition affects the motor and sensory functions of the larynx.
## **Why the Correct Answer is Right**
In bilateral recurrent laryngeal nerve palsy, the vocal cords are typically paralyzed in a paramedian position due to the loss of innervation from the posterior cricoarytenoid muscles, which are the only muscles responsible for opening (abducting) the glottis. Without this function, the vocal cords cannot move apart properly, leading to a narrow airway. This results in **inspiratory stridor** and potentially life-threatening airway obstruction. The correct answer relates to the characteristic presentation of this condition.
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option might suggest a different clinical presentation or consequence not directly related to bilateral recurrent laryngeal nerve palsy.
- **Option B:** Similarly, this might propose an alternative effect or symptom not specifically associated with bilateral palsy of the recurrent laryngeal nerves.
- **Option C:** This option could imply a different type of nerve involvement or a distinct clinical scenario.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that bilateral recurrent laryngeal nerve palsy often presents with **stridor**, which is a high-pitched sound heard during inhalation, indicating a significant obstruction of the airway. This condition may require emergency intervention, such as a tracheotomy, to secure the airway.
## **Correct Answer:** D. Stridor.