Question

Paralysis of jaw muscles is due to loss of function of which cranial nerve?
a. III
b. V
c. VII
d. X

Answer 1

Hint: The cranial nerve is defined as a set of twelve paired nerves that directly arise from the brain. Optic and olfactory nerves arise from the cerebrum while the remaining ten nerves arise from the brain. Cranial nerves are present on the ventral surface of the brain. Cranial nerves are the connections that connect the brain to different parts of the neck, trunk, and head.

Complete answer:
- The cranial nerve V is the trigeminal nerve also known as Dentist's nerve.
- Branches of this neuron are both motor and sensory in function.
- This nerve is the largest. It originated from the pons region of the brainstem.
- The first branch is ophthalmic and supplies an eye. The second branch is the maxillary branch it supplies to the maxilla i.e. lower jaw and the third branch is mandibular, it supplies to the tongue.
- Paralysis of the jaw muscle occurs due to the loss of function of the mandibular branch of the trigeminal nerve or V cranial nerve.
- III cranial nerve is oculomotor; its supply is for the eyeball muscle.
- VII cranial nerve is the facial cranial nerve.
- X cranial nerve is the vagus nerve and is the longest cranial nerve.

Hence, the correct answer is option (B).

Additional information:
There are a total of 12 cranial nerves they are as follows:
- Olfactory nerve
- Optic nerve
- Oculomotor nerve
- Trochlear nerve
- Trigeminal nerve
- Abducens nerve
- Facial nerve
- Vestibulocochlear nerve
- Glossopharyngeal nerve
- Vagus nerve
- Accessory nerve
- Hypoglossal nerve

Some cranial nerves take information from the sense organs to the brain, others are connected to internal organs such as the lungs and heart, and some cranial nerves control muscles.

Note: Paralysis is the loss of function of muscle in the part of the body. It occurs when there is something wrong in the way of information between the brain and the muscles. Paralysis can be partial or complete. Paralysis of jaw muscles occurs due to the loss of functioning of the mandibular branch of the V cranial nerve. It is different from facial paralysis which is due to the loss of functioning of the VII cranial nerve. All cranial nerves have particularly different functions in the body.