Structure associated with horizontal movement of eye is?
**Core Concept**
The horizontal movement of the eye is a complex process involving the coordinated action of multiple extraocular muscles and their associated nerves. The primary structure responsible for this movement is the **lateral rectus muscle**, which is innervated by the **abducens nerve (CN VI)**.
**Why the Correct Answer is Right**
The lateral rectus muscle plays a crucial role in the abduction of the eye, allowing it to move outward and away from the midline of the face. This muscle is responsible for the horizontal movement of the eye, facilitating functions such as reading, driving, and sports activities. The abducens nerve, which innervates the lateral rectus muscle, is responsible for transmitting signals from the brain to the muscle, enabling coordinated eye movements.
**Why Each Wrong Option is Incorrect**
**Option A:** The **medial rectus muscle** is responsible for adduction of the eye, not horizontal movement.
**Option B:** The **superior oblique muscle** is responsible for intorsion and depression of the eye, not horizontal movement.
**Option C:** The **inferior oblique muscle** is responsible for extorsion and elevation of the eye, not horizontal movement.
**Clinical Pearl / High-Yield Fact**
The lateral rectus muscle is the only extraocular muscle that is not innervated by the oculomotor nerve (CN III). This fact is crucial for diagnosing third cranial nerve palsy, as the affected eye will exhibit impaired adduction due to the involvement of the medial rectus muscle.
**Correct Answer:** C.