The vagus nerve is which numbered cranial nerve?

The vagus nerve is the tenth cranial nerve, written as cranial nerve X or CN X. It is the longest and most widely distributed cranial nerve, extending from the brainstem through the neck and chest into the abdomen.

Its name comes from the Latin vagus, meaning wandering, which reflects its extensive route through the body. The vagus carries both sensory and motor fibers. It communicates information from organs to the brain and sends parasympathetic signals that help regulate involuntary functions such as heart rate, breathing, swallowing, and digestion.

The nerve emerges from the medulla oblongata, passes through the jugular foramen in the skull, and gives branches to structures including the pharynx, larynx, heart, lungs, and gastrointestinal tract. Its influence on the voice and swallowing is why vagus-nerve damage can cause hoarseness or difficulty swallowing.

It is commonly confused with the ninth cranial nerve, the glossopharyngeal nerve, because both participate in swallowing and sensation in the throat. The fifth nerve is the trigeminal nerve, chiefly associated with facial sensation and chewing, while the seventh is the facial nerve.