The study of the motor fiber amounts of accessory nerve and its branches and the main trunk of phrenic nerve

Objective:To explore the motor fiber amounts of accessory nerve and its branches and the phrenic nerve trunk by histochemical method, and provide basic data for respiratory function reconstruction by transposition of accessory nerve to phrenic nerve in the rats with upper cervical cord injuries. Methods: Bilateral accessory nerves and their branches and phrenic nerve of 30 male rats were dissected under operating microscopy. All tissues were AchE histochemically stained with Kamorsky-root method. The motor fibers were counted with VIDS-Ⅲgraphical analyzer. Results: There were about 451±43 motor fibers in the proximal part of the accessory nerve, and those reaching sternocleidomastoid muscle were 182±12. The motor fibers of the superclavicular section of the accessory nerve were 279±29. There were 209±32 motor fibers in infraclavicular section of the accessory nerve before giving the medial and lateral branches. The motor fibers of the phrenic nerve trunk were about 237±41. Conclusions:The motor fiber amounts in the infraclavicular section of the accessory nerve, before giving medially horizontal and lateral branches are similar to those of the phrenic nerve trunk. It is possible to reconstruct respiratory function by transposition of accessory nerve to phrenic nerve in the rats with upper cervical cord injuries.