ABSTRACT
Objective To measure anatomic data related to the thyroid cartilage and cricoid cartilage and to analyze their implications for anterior spine surgery.Methods From January 2015 to February 2017,Cervical spine CT image data of 309 normal adults (195 males,114 females) in our department were retrospectively analyzed.The transverse diameters of the thyroid cartilage and the cricoid cartilage was measured at three different levels as follows:the superior border of the thyroid cartilage(SBTC),the inferior border of the thyroid cartilage(IBTC),and the inferior border of the cricoid cartilage(IBCC).At those levels,the corresponding level and transverse diameter of the cervical vertebra or intervertebral disc were also determined.Differences of anatomic parameters for each gender and level,and the relationship between the transverse diameter and height and weight were analyzed.Results The transverse diameters of the thyroid cartilage or cricoid cartilage and the corresponding cervical vertebra or intervertebral disc were associated significantly with height and weight.The transverse diameters of the thyroid cartilage or cricoid cartilage gradually decreased from the level of SBTC (44.30±4.97 mm) to the level of IBTC (41.39±4.62 mm),and the latter to the level of IBCC (26.36±3.79 mm),but increased from the level of SBTC (27.47±2.66 mm) to the level of IBTC (29.00±3.15 mm),and the latter to the level of IBCC (31.48±3.49 mm) for the cervical vertebra or intervertebral disc.Differences of the transverse diameters of the thyroid cartilage or cricoid cartilage and the cervical vertebra or intervertebral disc on three levels had statistical significance.The transverse diameters of each level had individual differences,while men were greater than those for women.The thyroid cartilage was routinely located above the C5 (56.9％ for male,86.0％ for female).Differences of the frequency between men and women on three levels had statistical significance.Conclusion The Individual and sex differences in the location of the thyroid cartilage and the size of the thyroid cartilage and the cricoid cartilage provided anatomical basis for predicting the difficulty of intraoperative exposure,incidence of esophageal injuries and early postoperative dysphagia.