**Question:** Dryness of eye is caused by injury to the facial nerve at-

A. Ophthalmic division
B. Temporal division
C. Lateral division
D. Medial division

**Core Concept:** The facial nerve (cranial nerve VII) has two main divisions: the ophthalmic (V2) and the temporal (V3) divisions. The ophthalmic division supplies blood supply to the eye, while the temporal division contains the lacrimal and some branches of the superior and inferior branches that supply the lacrimal gland, conjunctiva, and eyelids. The lateral division (V3) carries sensory fibers to the eyelids and the medial division (V3) carries motor fibers to the muscles of the eyelids and lacrimal gland.

**Why the Correct Answer is Right:** Dryness of the eye is caused by injury to the medial division of the facial nerve (V3), specifically to the motor fibers that innervate the lacrimal gland and the muscles of the eyelids. These fibers are responsible for the production of tears and their smooth functioning is essential for maintaining the lubrication and health of the eye. Injuries to the medial division can lead to reduced tear production and impaired eyelid closure, resulting in dryness and discomfort.

**Why Each Wrong Option is Incorrect:**

A. Ophthalmic division (V2) and its branches are responsible for supplying blood to the eye and not directly related to tear production or eyelid function.
B. Temporal division (V3) contains lacrimal and some branches of the superior and inferior branches that supply the lacrimal gland, conjunctiva, and eyelids. However, the correct answer is the medial division (V3) of the facial nerve, which is responsible for tear production and eyelid function.
C. Lateral division (V3) carries sensory fibers to the eyelids and the lacrimal gland, but it is not primarily responsible for tear production or eyelid function.
D. The medial division (V3) carries motor fibers for the lacrimal gland and the muscles of the eyelids, which are essential for tear production and eyelid closure, respectively.

**Clinical Pearl:** Proper functioning of the facial nerve is crucial for maintaining eye health and comfort. A thorough understanding of the divisions and branches of the facial nerve is essential in diagnosing and treating patients with eye-related conditions.