Nucleus ambiguus
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Brain: Nucleus ambiguus
Transverse section of medulla oblongata below the middle of the olive. ("Nucleus ambiguus" labeled at center right.)
Gray's	subject #187 779
NeuroNames	hier-762

The nucleus ambiguus (literally "ambiguous nucleus") is a region of histologically disparate cells located just dorsal (posterior) to the inferior olivary nucleus in the lateral portion of the upper (rostral) medulla.

This nucleus gives rise to the efferent motor fibers of the vagus nerve (CN X) terminating in the laryngeal and pharyngeal muscles, as well as to the efferent motor fibers of the glossopharyngeal nerve (CN IX) terminating in the stylopharyngeus and the accessory nerve (CN XI) which innervates other muscles of the soft palate and pharynx.

Areas supplied

The muscles supplied by the vagus (included with this is the cranial part of the accessory nerve), such as levator veli palatini, are also necessary to swallow properly through integration by the nucleus of the solitary tract. The vagus also supplies the upper part of the esophagus, and other parts of the pharynx and larynx.

As well as motor functions, nucleus ambiguus also contains the preganglionic neurons for the heart¹.

Additional images

Section of the medulla oblongata at about the middle of the olive.

The cranial nerve nuclei schematically represented; dorsal view. Motor nuclei in red; sensory in blue.

Nuclei of origin of cranial motor nerves schematically represented; lateral view.

The formatio reticularis of the medulla oblongata, shown by a transverse section passing through the middle of the olive.

References

External links

• Medical Neurosciences discuss the nucleus ambiguus.
• -1664090053 at GPnotebook