====== Vocal cord ======

Classically the 11th cranial nerve (CN XI, or [[accessory nerve]]) is described as having a cranial and a spinal root, the latter arising from the upper segments of the [[spinal cord]] through a number of very fine rootlets. According to classical knowledge, the cranial root gives motor innervation to the [[vocal cord]]s, whereas the spinal root provides the motor innervation of the [[sternocleidomastoid muscle]] (SCM) and of the upper portions of the trapezius muscle (TZ). The specific function of each of the rootlets of the spinal component is not well known. 

The function of each of the rootlets of CN XI appears to be specific. The cranial root contributes, independently of the spinal root, to the innervation of the vocal cords, which makes it a specific entity. The spinal root innervates the SCM and TZ with a cranio-caudal motor organization of its cervical rootlets
((Brînzeu A, Sindou M. Functional anatomy of the accessory nerve studied through
intraoperative electrophysiological mapping. J Neurosurg. 2016 Apr 8:1-9. [Epub
ahead of print] PubMed PMID: 27058194.
)).

Endotracheal surface electrodes allow identification of vocal cord motor rootlets in the cerebello pontine angle (CPA). Worsening of compound motor action potentials (CMAPs) parameters might indicate functional impairment. These aspects support the use of endotracheal surface electrodes in selected patients in whom the [[vagus nerve]] might be at risk during CPA surgery
((Romagna A, Rachinger W, Schwartz C, Mehrkens JH, Betz C, Briegel J, Schnell O,
Tonn JC, Schichor C, Thon N. Endotracheal Tube Electrodes to Assess Vocal Cord
Motor Function During Surgery in the Cerebellopontine Angle. Neurosurgery. 2015
Sep;77(3):471-8; discussion 478. doi: 10.1227/NEU.0000000000000854. PubMed PMID: 
26103443.
)).

The majority of motor fibers of the [[lower cranial nerve]]s run through the caudal part of the rootlets at the [[cerebellomedullary cistern]], and the maximal electromyographic response at the vocal cord was elicited at the most caudal or second most caudal rootlet
((Wanibuchi M, Akiyama Y, Mikami T, Komatsu K, Sugino T, Suzuki K, Kanno A,
Ohtaki S, Noshiro S, Mikuni N. Intraoperative Mapping and Monitoring for Rootlets
of the Lower Cranial Nerves Related to Vocal Cord Movement. Neurosurgery. 2016
Jun;78(6):829-34. doi: 10.1227/NEU.0000000000001109. PubMed PMID: 26544957.)).

===== Vocal cord paresis =====

[[Vocal cord paresis]].

===== Vocal cord paralysis =====

[[Vocal cord paralysis]].