Loss of contraction or traction

In patients with superior laryngeal nerve injury, the ipsilateral circumnuclei lose their contraction or traction during vocalization. Due to the anatomical relationship, cervical nerve injuries often occur simultaneously with vascular injuries. The higher the injury location, the more multiple nerve injuries; the middle and lower neck injuries, more single nerve injury. In facial and neck injuries, nerve damage accounts for 10% to 15%. Among them, brachial plexus, spinal cord, recurrent laryngeal nerve and vagus nerve are more common. The superior laryngeal nerve comes from the nodular ganglion of the vagus nerve, its location is close to the jugular foramen, and it is divided into internal and external branches on the plane of the hyoid bone. The outer branch is often closely associated with the superior thyroid artery on the way down, and is usually located in front of the superior thyroid artery (Figures 1 and 2). According to the autopsy of 200 cases of Moosman, 21% of the outer branches walked in an uncertain direction, 15% were located in the thyroid sheath, and 6% were located between the branches of the superior thyroid artery. According to Meng Zhaohui et al.'S (1976) observation of the anatomy of the laryngeal nerve, the superior laryngeal nerve and the superior thyroid artery are closely associated with each other. Among them, the nerve walking behind the superior thyroid artery accounts for 89.3%, the former precedes the artery accounts for 6.7%, and the artery branches The latter accounted for 4%.