From the Guidelines
The cranial root of the accessory nerve (CN XI) and the vagus nerve (CN X) originate from the nucleus ambiguus.
Nerve Origins
- The accessory nerve (CN XI) has a small cranial root that originates from the nucleus ambiguus within the medulla oblongata, as well as a large spinal root originating from the ventral horn of the spinal cord 1.
- The vagus nerve (CN X) is also known to originate from the nucleus ambiguus, although this is not explicitly stated in the provided study, it is a well-established fact in neuroanatomy.
Clinical Relevance
The nucleus ambiguus is a critical structure in the medulla oblongata, and damage to this area can result in various cranial nerve palsies, including those affecting the accessory and vagus nerves 1.
From the Research
Nerves Originating from the Nucleus Ambiguus
The nucleus ambiguus is a nucleus located in the medulla oblongata, and it is the source of several important nerves. The following nerves originate from the nucleus ambiguus:
Specific Branches of the Nerves
Some specific branches of these nerves also originate from the nucleus ambiguus, including:
- The recurrent laryngeal nerve, a branch of the vagus nerve 2
- The pharyngeal branches of the vagus nerve 4
- The visceral branches of the vagus nerve 4, 5
- The laryngomotor subdivision of the vagus nerve 4
Organization of the Nucleus Ambiguus
The nucleus ambiguus is organized into different subdivisions, each corresponding to a specific nerve or branch:
- The pharyngomotor subdivision, which gives origin to the innervation of the pharyngeal muscles 4
- The visceromotor subdivision, which consists of small and medium-sized cells labeled by way of the visceral branches of the vagus 4
- The laryngomotor subdivision, which supplies the sphincter muscles of the larynx 4
- The accessory nerve subdivision, which is located in the lower medulla and the rostral spinal cord 4