Which nerve is responsible for inferior and lateral movement of the eye?

The trochlear nerve is responsible for inferior and lateral movement of the eye. This nerve innervates the superior oblique muscle, which plays a crucial role in controlling eye movements, particularly during adduction and depression of the eyeball. When the superior oblique muscle contracts, it allows the eye to move downward and outward, facilitating a range of visual tracking and gaze adjustments.

Understanding the role of this nerve is essential, as eye movements are important for visual coordination and balance. The trochlear nerve has the distinction of being the smallest cranial nerve in terms of the number of fibers and is the only cranial nerve that exits the brainstem from the dorsal aspect. This anatomical feature highlights its unique pathway in the nervous system.

Other nerves involved in eye movement, such as the oculomotor nerve, primarily control movements related to elevation and adduction, as well as parasympathetic functions like pupil constriction. The facial and glossopharyngeal nerves have different roles related to facial expression and autonomic functions, respectively, and do not directly influence eye movement.