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Dorsal nucleus of vagus nerve

The dorsal nucleus of the vagus nerve (also known as the dorsal motor nucleus of the vagus) is a parasympathetic motor nucleus located in the medulla oblongata. It provides preganglionic parasympathetic fibers to thoracic and abdominal viscera via the vagus nerve and plays a central role in autonomic regulation of cardiovascular, respiratory, and gastrointestinal functions.

It is a key component of the vagal parasympathetic system and an important anatomical landmark in brainstem neuroanatomy and imaging.

Synonyms

  • Dorsal motor nucleus of vagus

  • Dorsal vagal nucleus

Location

  • Forms part of the floor of the fourth ventricle

  • Situated medial to the solitary nucleus

  • Posterior to the inferior olivary nucleus

  • Anterior to the hypoglossal trigone

  • Extends longitudinally through the medulla

Anatomical organization

  • Nuclear type:

    • Visceral efferent (general visceral efferent, GVE)

  • Cell bodies:

    • Preganglionic parasympathetic neurons

  • Fiber exit:

    • Axons course ventrolaterally to exit the medulla as part of the vagus nerve

Relations

Anteriorly:

  • Inferior olivary nucleus

Posteriorly:

  • Fourth ventricle

Medially:

  • Hypoglossal nucleus

Laterally:

  • Solitary nucleus and tract

Superiorly:

  • Pontomedullary junction

Inferiorly:

  • Closed medulla near the level of the decussation of pyramids

Associated nerve

  • Vagus nerve (cranial nerve X):

    • Carries preganglionic parasympathetic fibers from this nucleus

    • Fibers synapse in autonomic ganglia within thoracic and abdominal organs

Structures innervated

  • Heart (cardiac plexus)

  • Lungs (pulmonary plexus)

  • Gastrointestinal tract from esophagus to proximal two-thirds of the transverse colon

  • Associated visceral glands

Function

  • Parasympathetic control of heart rate: Reduces heart rate and conduction velocity

  • Respiratory modulation: Influences bronchoconstriction and secretions

  • Gastrointestinal regulation: Controls motility, secretion, and peristalsis

  • Visceral homeostasis: Maintains autonomic balance of thoracoabdominal organs

MRI appearance 

T1-weighted images:

  • Nucleus: Isointense to surrounding gray matter of the medulla

T2-weighted images:

  • Normal: Intermediate signal similar to adjacent brainstem gray matter

FLAIR:

  • Normal: Homogeneous signal within dorsal medulla

Diffusion-weighted imaging (DWI):

  • Normal: No diffusion restriction

Post-contrast T1-weighted images:

  • Normal: No enhancement

CT appearance (normal)

Non-contrast CT:

  • Nucleus: Not individually visualized

Post-contrast CT:

  • Normal: No focal enhancement

MRI image

MRI Dorsal nucleus of vagus nerve axial anatomy image -img-00000-00000