How many cranial nerves are responsible for the six extraocular muscles?

The six extraocular muscles that control eye movement are innervated by three cranial nerves: the oculomotor nerve (cranial nerve III), the trochlear nerve (cranial nerve IV), and the abducens nerve (cranial nerve VI). The oculomotor nerve is primarily responsible for innervating four of the extraocular muscles (the superior rectus, inferior rectus, medial rectus, and inferior oblique). The trochlear nerve innervates the superior oblique muscle, while the abducens nerve controls the lateral rectus muscle.

Therefore, the correct answer reflects the number of cranial nerves involved in the control of all six extraocular muscles. Each cranial nerve plays a distinct role in facilitating coordinated, precise movements of the eyes, which is essential for proper vision and alignment. Understanding the cranial nerve innervation of these muscles is crucial for ophthalmic professionals in diagnosing and treating various eye movement disorders.