The cranial nerves are a set of twelve pairs of nerves that travel to and from the brain. Each has a different function. For example, the olfactory nerve is essential for detecting smells. The ...

The trochlear nerve, also known as cranial nerve 4 (CN IV), controls the superior oblique muscle in your eye. This muscle allows you to move your eyeball down and shift your gaze from side to side.

The optic nerve is located in the back of the eye. It is also called the second cranial nerve or cranial nerve II. It is the second of several pairs of cranial nerves.

The shoulder plays a key role in the blood flow to the arms. The armpit and shoulder serve as the meeting place for the torso and arms, so major vessels close to the heart travel through these areas.