Dear Doctors: I had an episode where it felt like my left eye went out of alignment and I couldn’t focus. A brain scan was clear, but the doctor said it’s cranial nerve palsy. He says it’s from a ...

A complex system of nerves and muscles enables the human eye to blink, gaze, and shift focus. The trochlear nerve is one of six cranial nerves that carry electrical impulses from the brain to the eye.

The trochlear nerve is also known as cranial nerve IV (CN-IV). It is the only cranial nerve that emerges dorsally from the brain (near the back), giving it the longest pathway. It is the smallest ...