Which muscle is controlled by the third cranial nerve?

The muscle controlled by the third cranial nerve, also known as the oculomotor nerve, is the medial rectus muscle. This nerve innervates several eye muscles that are responsible for eye movements, including:

• The medial rectus, which adducts the eye (moves it towards the nose).

• The superior rectus, which elevates the eye.

• The inferior rectus, which depresses the eye.

• The inferior oblique, which assists in elevating and externally rotating the eye.

Understanding the actions of these muscles is crucial for anyone studying ophthalmology or related fields. The oculomotor nerve plays a vital role in coordinating eye movement and maintaining proper alignment of the eyes for clear vision.

In contrast, the lateral rectus muscle is innervated by the sixth cranial nerve (abducens), and the superior oblique muscle is controlled by the fourth cranial nerve (trochlear). These distinctions are important for understanding the specific roles and innervations of the ocular muscles.