Nucleus ambiguus

Last revised by Craig Hacking on 12 Oct 2022

Citation, DOI, disclosures and article data

Citation:

Rothe C, Hacking C, Gaillard F, et al. Nucleus ambiguus. Reference article, Radiopaedia.org (Accessed on 18 Apr 2024) https://doi.org/10.53347/rID-75944

DOI:

https://doi.org/10.53347/rID-75944

Permalink:

https://radiopaedia.org/articles/75944

rID:

75944

Article created:

9 Apr 2020, Chris Rothe

Disclosures:

At the time the article was created Chris Rothe had no recorded disclosures.

View Chris Rothe's current disclosures

Last revised:

12 Oct 2022, Craig Hacking ◉ ◈

Disclosures:

At the time the article was last revised Craig Hacking had the following disclosures:

Philips Australia, Paid speaker at Philips Spectral CT events (ongoing)

These were assessed during peer review and were determined to not be relevant to the changes that were made.

View Craig Hacking's current disclosures

Revisions:

16 times, by 5 contributors - see full revision history and disclosures

Systems:

Central Nervous System

Sections:

Anatomy

The nucleus ambiguus is a large longitudinal nucleus within the medulla oblongata that provides motor innervation to muscles of the pharynx, larynx and soft palate in addition to housing preganglionic nuclei involved in the parasympathetic nervous system augmentation of heart rate ^1,2.

Gross anatomy

The nucleus ambiguus is a paired nucleus located in the lateral aspect of the rostral medulla.

It lies dorsal to the inferior olivary nucleus and ventromedial to the spinal nucleus and tract of the trigeminal nerve (CN V). It is located medial to the lateral spinothalamic tract.

The dorsal motor nucleus of the vagus nerve (CN X) and the solitary tract nucleus both lie dorsal to the nucleus ambiguus, and their respective fibers course around the dorsolateral aspect of the nucleus ambiguus.

Innervation

The nucleus ambiguus houses cell bodies which provide motor fibers to the glossopharyngeal (CN IX), vagus (CN X) and spinal accessory nerves (CN XI), which pass laterally from the nucleus ambiguus to exit the medulla in the postolivary sulcus.

The nucleus ambiguus provides motor innervation to the stylopharyngeus muscle with the efferent fibers traveling within the glossopharyngeal nerve (CN IX).

The nucleus ambiguus also provides motor innervation to the superior, middle and inferior pharyngeal constrictor muscles in addition to the muscles of the soft palate (palatopharyngeus, salpingopharyngeus, levator veli palatini, palatoglossus and the muscles of the uvula). These efferent fibers arising from the nucleus ambiguus travel through pharyngeal branches of the vagus nerve (CN X) which arise from the inferior (nodose) vagal ganglion.

The external laryngeal nerve supplies the cricothyroid muscle (the only intrinsic muscle of the larynx not supplied by the recurrent laryngeal nerve).

The recurrent laryngeal nerve provides motor innervation to all of the intrinsic laryngeal muscles except the cricothyroid muscle.

The nucleus ambiguus also houses preganglionic neurons which contribute to vagal parasympathetic control of heart rate.