Which extraocular muscle is primarily responsible for adducting the eye (moving the eyeball medially toward the nose)?

• A. Medial rectus
• B. Lateral rectus
• C. Inferior rectus
• D. Superior oblique

Answer: (A)

Verified step by step guidance

1. Understand the term 'adduction' in the context of eye movement: adduction refers to moving the eyeball medially, or toward the nose (the midline of the body).
2. Recall the six extraocular muscles that control eye movement: medial rectus, lateral rectus, superior rectus, inferior rectus, superior oblique, and inferior oblique.
3. Identify the primary function of each muscle: the medial rectus muscle is responsible for moving the eye inward (adduction), while the lateral rectus moves it outward (abduction).
4. Eliminate muscles that do not primarily cause adduction: lateral rectus causes abduction, superior oblique mainly causes depression and intorsion, and inferior rectus causes depression and extorsion.
5. Conclude that the medial rectus muscle is the primary muscle responsible for adducting the eye, moving it medially toward the nose.