accessory nerve

In anatomy, the accessory nerve is a nerve that controls specific muscles of the neck. As a part of it is traditionally believed to originate in the brain, it is considered a cranial nerve. Based on its location relative to other such nerves, it is designated the eleventh of twelve cranial nerves, and is thus abbreviated CN XI. Although anatomists typically refer to the accessory nerve in singular, there are in reality two accessory nerves, one on each side of the body.
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Noun
1. arises from two sets of roots (cranial and spinal) that unite to form the accessory nerve trunk
(synonym) spinal accessory, nervus accessorius, eleventh cranial nerve
(hypernym) cranial nerve