Innervation of Human Cricopharyngeal Muscle By Recurrent Laryngeal and External Branch of Superior Laryngeal Nerve

Electromyography recordings were accomplished with a pair of needle electrodes inserted through the CP muscle, which were plugged into the third and fourth channels of interface-connector box.The recurrent laryngeal nerve(RLN), vagus nerve, external branch of the superior laryngeal nerve(EBSLN) and pharyngeal plexus were stimulated with a current of 1 mA and a frequency of 4 MHz and the event threshold at 100 microV.