The Vagus Nerve, also known as the 10th cranial nerve, is a long nerve that runs from the brainstem to the abdomen and is responsible for regulating various bodily functions, including heart rate, digestion, and breathing. There are several synonyms for this nerve, including the pneumogastric nerve, cranial nerve X, and the wandering nerve. The term pneumogastric refers to the nerve's connections to both the lungs (pneumo) and stomach (gastric). The nerve is called the wandering nerve because it has multiple branches that spread throughout the body, and it plays a crucial role in maintaining overall health and well-being.