Question

Which of the following cranial nerve is instrumental in motor function:

• A. \( \text{Vestibulocochlear} \)
• B. \( \text{Olfactory} \)
• C. \( \text{Accessory} \)
• D. \( \text{Optic} \)

Hint:

Cranial nerves involved in motor functions include: 
1. Oculomotor (III): Eye movement. 
2. Trochlear (IV): Eye movement. 
3. Abducens (VI): Eye movement. 
4. Accessory (XI): Neck and shoulder movements. 
5. Hypoglossal (XII): Tongue movement.

Answer 1

The Correct Option is C

Step 1: Understanding cranial nerve classifications. Cranial nerves are classified based on their primary functions: 
1. Sensory nerves (e.g., Olfactory and Optic) are involved in sensation. 
2. Motor nerves (e.g., Accessory) control muscle movements. 
3. Mixed nerves (e.g., Facial) have both sensory and motor functions. 

Step 2: Role of the accessory nerve. The accessory nerve, also known as cranial nerve XI, is a motor nerve that innervates the sternocleidomastoid and trapezius muscles. It facilitates movements of the head, neck, and shoulders. 

Step 3: Comparison with other options. - Option \( (A) \): Vestibulocochlear nerve (cranial nerve VIII) is a sensory nerve responsible for hearing and balance. 
- Option \( (B) \): Olfactory nerve (cranial nerve I) is a sensory nerve responsible for the sense of smell. 
- Option \( (D) \): Optic nerve (cranial nerve II) is a sensory nerve responsible for vision. 

Conclusion: The accessory nerve (cranial nerve XI) is the correct answer for being instrumental in motor function.