Anatomy books

Wednesday, July 27, 2022

nucleus ambiguus

The nucleus ambiguus runs in a rostral to caudal direction in the medulla and is located in the ventrolateral reticular formation, posterior to the inferior olivary nuclear complex and anteromedial to the spinal trigeminal nucleus 
 
The rostral portion of the nucleus ambiguus gives rise to special visceral efferent fibers of the glossopharyngeal nerve, which innervate the stylopharyngeus muscle.
This muscle originates from the styloid process and descends between the internal and external carotid arteries to the upper wall of the pharynx.
Contraction of the stylopharyngeus muscle aids in raising the larynx and elevating and expanding the pharynx during swallowing.
 The nucleus ambiguus is also the source of special visceral efferent fibers of cranial nerves X and XI, which together with cranial nerve IX innervate the muscles of the pharynx and larynx.

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