Question

This muscle is innervated by which of

the following cranial nerves along with which other muscle?
a. CN X, thyroarytenoid muscle
b. CN IX platysma
C. CN VII, risorius muscle

Answer 1

The sternocleidomastoid and trapezius muscles are innervated by the spinal accessory nerve (CN XI), which is responsible for certain head movements and shoulder elevation. The options given in the question do not correctly match the muscle to the nerve, and an error might be present within the question's structure.

Step-by-step explanation:

The student's question seems to refer to cranial nerves and their innervation of specific muscles. Based on the content provided, it can be inferred that the muscle in question is the sternocleidomastoid or trapezius, which are innervated by the accessory nerve, also known as the spinal accessory nerve (CN XI). This cranial nerve is responsible for certain head movements and shoulder elevation.

• Thyroarytenoid muscle is innervated by the vagus nerve (CN X), not the accessory nerve.
• Platysma is innervated by the facial nerve (CN VII), which also innervates the risorius muscle.
• The accessory nerve does not innervate muscles involved in the gag reflex; that is a function of the glossopharyngeal (CN IX) and vagus nerves (CN X).

Therefore, the correct answer to the student's question, based on the information provided, would be the accessory nerve innervates the sternocleidomastoid muscle alongside the trapezius muscle. This was not one of the options given, suggesting there may be an error in the question's options or that additional context is needed.