The left vagus further gives off thoracic cardiac branches, breaks up into the pulmonary plexus, continues into the esophageal plexus, and enters the abdomen as the anterior vagal trunk in the esophageal hiatus of the diaphragm. Branches Pharyngeal nerve Superior laryngeal nerve Superior cervical cardiac branches of vagus nerve Inferior cervical cardiac branch Recurrent laryngeal nerve Thoracic cardiac branches Branches to the pulmonary plexus Branches to the esophageal plexus Anterior vagal trunk Posterior vagal trunk Hering–Breuer reflex in alveoli The vagus runs parallel to the common carotid artery and internal jugular vein inside the carotid sheath. Nuclei The vagus nerve includes axons which emerge from or converge onto four nuclei of the medulla: The dorsal nucleus of vagus nerve – which sends parasympathetic output to the viscera, especially the intestines The nucleus ambiguus – which gives rise to the branchial efferent motor fibers of the vagus nerve and preganglionic parasympathetic neurons that innervate the heart The solitary nucleus – which receives afferent taste information and primary afferents from visceral organs The spinal trigeminal nucleus – which receives information about deep/crude touch, pain, and temperature of the outer ear, the dura of the posterior cranial fossa and the mucosa of the larynx Development The motor division of the glossopharyngeal nerve is derived from the basal plate of the embryonic medulla oblongata, while the sensory division originates from the cranial neural crest. Function The vagus nerve supplies motor parasympathetic fibers to all the organs (except the adrenal glands), from the neck down to the second segment of the transverse colon. The vagus also controls a few skeletal muscles, including: Cricothyroid muscle Levator veli palatini muscle Salpingopharyngeus muscle Palatoglossus muscle Palatopharyngeus muscle Superior, middle and inferior pharyngeal constrictors Muscles of the larynx (speech). This means that the vagus nerve is responsible for such varied tasks as heart rate, gastrointestinal peristalsis, sweating, and quite a few muscle movements in the mouth, including speech (via the recurrent laryngeal nerve). It also has some afferent fibers that innervate the inner (canal) portion of the outer ear (via the auricular branch, also known as Arnold's or Alderman's nerve) and part of the meninges. Efferent vagus nerve fibers innervating the pharynx and back of the throat are responsible for the gag reflex. In addition, 5-HT3 receptor-mediated afferent vagus stimulation in the gut due to gastroenteritis is a cause of vomiting. Stimulation of the vagus nerve in the cervix