spinal accessory nucleus(redirected from Accessory nucleus)
spinal accessory nucleus
A branchial motor column nucleus that extends caudally from the end of the nucleus ambiguus into the ventral horn of spinal cord segments C1-C4. Axons of the neurons in the spinal accessory nucleus leave the spinal cord through lateral (not ventral) rootlets and collect into a thin nerve that runs up along the side of the cord and into the skull through the foramen magnum. There, this nerve joins with rootlets from the nucleus ambiguus to form the spinal accessory nerve (CN XI).
See also: nucleus
Medical Dictionary, © 2009 Farlex and Partners