Cranial nerve X, known as the vagus nerve, is the tenth and one of the most crucial nerves. All twelve cranial nerves, including the vagus nerve, either exit or enter the skull, unlike spinal nerves which emerge from the spine. Originating from the medulla oblongata in the brainstem, the vagus nerve plays a vital role in the body's functioning. It provides nerve fibers to the throat, voice box, windpipe, lungs, heart, and much of the digestive tract up to the transverse colon. Additionally, it carries sensory information from the ear, tongue, pharynx, and larynx.The name "vagus," meaning "wandering" in Latin, is fitting due to the nerve's extensive path from the brainstem to the colon. If the vagus nerve is completely severed, a distinct syndrome occurs. The soft palate on the affected side droops, the gag reflex on that side is lost, and the voice becomes hoarse and nasal. The vocal cord on the impacted side becomes immobile, leading to dysphagia (difficulty swallowing) and dysphonia (difficulty speaking).One of its notable branches is the recurrent laryngeal nerve. After branching off from the vagus nerve, it descends into the chest before looping back to the larynx. Diseases within the chest, such as tumors or aneurysms of the aortic arch or heart, can damage the recurrent laryngeal nerve, resulting in laryngeal palsy and paralysis of the larynx on the affected side. Damage to the vagus nerve before it branches can also cause laryngeal palsy.
