The Applied Anatomy Study Of Atlantoaxial Joint Through The Retropharyngeal Space Of Superior Cervical

Objective:To provide anatomical data and confirm the safe region for exposion ofatlantoaxial joint through the operative route of retropharyngeal space in uppercervical vertebra..Materials and methods：1. Seventeen (33sides) adult head and neck cadavers which were soaked in theliquor of formalin perfused with red latex were observed.2. Carotid triangle and such surrounding structures as carotid sheath, superiorthyroid artery, superior laryngeal nerve, lingual artery, hypoglossal nerve, the body ofhyoid bone and the tip of the greater horn of the hyoid bone (THB) were revealed.The measured values were as follows: Firstly, the distance between THB and thestarting point of superior thyroid artery and lingual artery at the original site fromcarotid sheath, the beginning of surperior laryngeal artery, the entrance point ofsurperior laryngeal artery and internal branch of the surperior laryngeal nerve intothyrohyoid membrane, also with lingual artery and hypoglossal nerve into mylohyoidmuscle respectively. Secondly, the lengths from THB to the intersection of surperiorlaryngeal nerve and hypoglossal nerve with carotid sheath respectively, thebifurcation point of surperior laryngeal nerve branches. Finally, the closest distancefrom THB to superior thyroid arterial trunk, surperior laryngeal nerve, lingual arteryand hypoglossal nerve.3. The surgical approach of retropharyngeal space in upper cervical vertebra wasdetermined preliminarily through the analysis of actual measured data.4. The feasibility of this techniques were be verified by operative procedure inhuman cadaver specimens. Results:1. The distance between THB and the starting point of superior thyroid artery andlingual artery at the original site from carotid sheath were (0.907±0.131) cm and(1.221±0.167) cm. THB to the beginning of surperior laryngeal artery was(1.196±0.283) cm. The values from THB to the entrance point of surperior laryngealartery and internal branch of the surperior laryngeal nerve into thyrohyoid membranewere (2.002±0.114) cm and (1.655±0.172) cm. The lengths from THB to the entranceof lingual artery and hypoglossal nerve into mylohyoid muscle were (1.666±0.522)cm and (2.107±0.404) cm separately.2. The lengths from THB to the intersection of surperior laryngeal nerve andhypoglossal nerve with carotid sheath were (0.970±0.291) cm and (1.717±0.373) cm.THB to the bifurcation point of surperior laryngeal nerve branches was (1.061±0.202)cm.3. The closest distance from THB to superior thyroid arterial trunk, surperiorlaryngeal nerve, lingual artery and hypoglossal nerve were (1.278±0.240) cm,(0.627±0.283) cm,(0.864±0.268) cm and (1.426±0.263) cm respectively.Conclusion:To exposure atlantoaxial joint, along with the body of hyoid bone and the tip of thegreater horn of the hyoid bone (THB): It could be safely used through retropharyngealspace in upper cervical vertebra. Surperior laryngeal nerve should be protected strictlyduring operation, Which is between the above interior region of below0.627±0.283cm after THB and the below after region of interior0.864±0.268cm above THB.