Location and morphometry of the thyroid isthmus in adult Korean cadavers

The thyroid isthmus has different measurements in its width, height, and thickness, and its location with respect to the tracheal rings has been inconsistent, among the anatomical literature. This study was performed to clarify the location and morphometric characteristics of the thyroid isthmus. One hundred thyroid isthmuses of adult Korean cadavers (gender 58 males and 42 females, mean age 62.9 years, range 19-94 years) were used for this study. The distances from the inferior border of the cricoid cartilage to the superior and inferior margins of the isthmus were 4.9 ± 3.7 and 20.8 ± 5.8 mm, respectively. The width, height, and thickness of the thyroid isthmus were 11.1 ± 6.2, 15.9 ± 5.8 and 3.4 ± 1.7 mm, respectively. The thyroid isthmus was located on the 2nd to 4th, 1st to 3rd, and 1st to 4th tracheal rings, in 22, 18 and 18 % of the specimens, respectively. These results are expected to further the current knowledge of the location and morphometry of the thyroid isthmus and provide helpful information for surgical procedures in this region.