The nucleus ambiguus on each side is a motor nucleus within the medulla of the brainstem. It lies dorsomedial to the spinal lemniscus and ventral to the nucleus of tractus solitarius.

It supplies skeletal muscle fibres via three cranial nerves:

• glossopharyngeal nerve: stylopharyngeus muscle
• vagus and cranial root of accessory nerve:
• pharyngeal branch to the following muscles:
• levator palati
• salpingopharyngeus
• palatopharyngeus
• palatoglossus
• all the pharyngeal constrictors
• striated muscle of the oesophagus
• superior laryngeal nerve to cricothryroid muscle
• recurrent laryngeal nerve to intrinsic muscles of the larynx