Morphometry of isthmus of thyroid gland in Bangladeshi cadaver.

This cross sectional descriptive study was carried out to determine the length, breadth & thickness of isthmus of thyroid gland of Bangladeshi people. To fulfill this aim sixty postmortem tissue blocks containing thyroid gland and its neighbouring structures were collected by convenience sampling technique from 48 male and 12 female cadavers of different age groups, age ranging from 11 to 70 years and fixed and preserved in 10% formol-saline solution. Specimens were collected from dead bodies autopsied on different dates from October'2004 to February'2005 at the autopsy laboratory of Forensic Medicine Department of Mymensingh Medical College, Mymensingh, Bangladesh. Gross and fine dissection was carried out to study the length, breadth and thickness of isthmus of thyroid gland. In the present study, observed findings were compared with those of Western and Bangladeshi researchers. It was seen that the mean±SD lengths of isthmus were 10.42±7.49 mm, 10.17±5.70 mm and 9.33±6.64) mm in Group A(upto 18 years), B(19 to 45 years) and C(>45 years) respectively. Highest length (30mm) was observed in Group A and lowest length (2mm) was observed in Group C. Variance analysis showed that there was no significant difference in mean length between the age groups (F=0.086, p=0.918). The mean±SD values of breadth were 13.66±5.06 mm, 14±5.41 mm and 12.27±3.97 mm in Group A, B and C respectively. In the ranges, there was much overlapping among the groups. In Group B breadth of the isthmus was greater than other age groups. But these differences were statistically not significant, where F=0.430 & p=0.654. It was interesting to note that in this study the mean breadth of isthmus was significantly greater than the mean length (where, t=-2.727 and p=0.01). In the present study the mean±SD thickness of the isthmus of thyroid glands were 4.91±1.78 mm, 4.72±2.68 mm and 4.45±1.36 mm in three age groups respectively & the thickness of isthmus of thyroid gland was also greater in Group B than other two groups. But the variance analysis reveals that, there was insignificant difference in the thickness (F=0.133, p=0.876) of isthmus of thyroid gland among different age groups.