The spinal accessory nucleus lies within the cervical

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spi ...

(C1-C5) in the posterolateral aspect of the anterior horn. The

nucleus ambiguus The nucleus ambiguus ("ambiguous nucleus" in English) is a group of large motor neurons, situated deep in the medullary reticular formation named by Jacob Clarke. The nucleus ambiguus contains the cell bodies of neurons that innervate the muscles ...

is classically said to provide the "cranial component" of the

accessory nerve The accessory nerve, also known as the eleventh cranial nerve, cranial nerve XI, or simply CN XI, is a cranial nerve that supplies the sternocleidomastoid and trapezius muscles. It is classified as the eleventh of twelve pairs of cranial nerv ...

. However, the very existence of this cranial component has been recently questioned and seen as contributing exclusively to the

vagus nerve The vagus nerve, also known as the tenth cranial nerve, cranial nerve X, or simply CN X, is a cranial nerve that interfaces with the parasympathetic control of the heart, lungs, and digestive tract. It comprises two nerves—the left and right ...

. The terminology continues to be used in describing both human anatomy, and that of other animals.

Additional images

File:Gray697.png, Nuclei of origin of cranial motor nerves schematically represented; lateral view. File:Gray698.png, Primary terminal nuclei of the afferent (sensory) cranial nerves schematically represented; lateral view.

References

External links

Sylvius

University of New Mexico

{{Spinal cord Accessory nerve Cranial nerve nuclei Medulla oblongata