Anatomy of the spinal root of accessory nerve - Firm in texture - Arises from motor cells in the lateral part of the anterior column of the gray substance of the medulla spinalis - Extends as low as the fifth cervical nerve - Passes through the lateral funiculus of the medulla spinalis - Emerges on the surface and forms a single trunk

Pathway of the spinal root of accessory nerve - Ascends between the ligamentum denticulatum and the posterior roots of the spinal nerves - Enters the skull through the foramen magnum - Directed to the jugular foramen - Lies in the same sheath of dura mater as the vagus nerve - Separated from the vagus nerve by a fold of the arachnoid

Connections of the spinal root of accessory nerve - Receives filaments from the cranial part of the nerve in the jugular foramen - May join the vagus nerve for a short distance and then separate again - Runs in front of or behind the internal jugular vein as it exits the jugular foramen - Gives filaments to the Sternocleidomastoideus muscle - Joins with branches from the second cervical nerve

Course of the spinal root of accessory nerve - Descends obliquely behind the Digastricus and Stylohyoideus muscles - Pierces the Sternocleidomastoideus muscle - Courses obliquely across the posterior triangle of the neck - Ends in the deep surface of the Trapezius muscle - Forms a plexus with the third and fourth cervical nerves beneath the Trapezius

Additional information - The spinal root of accessory nerve article is a stub - The article can be expanded on Wikipedia - Retrieved from https://en.wikipedia.org/w/index.php?title=Spinal_root_of_accessory_nerve&oldid=1130256580 - Categories: Wikipedia articles incorporating text from the 20th edition of Grays Anatomy (1918), Accessory nerve, Neuroanatomy stubs - Hidden categories: Articles with TA98 identifiers, All stub articles