Variations in the anatomy of the thyroid gland: clinical implications of a cadaver study.

Surgical removal of the thyroid gland is associated with risk of damage to the parathyroid glands, external branch of superior laryngeal nerves, inferior laryngeal nerves, and haematoma due to vascular damage and the chance of residual thyroid tissue being left in case of cancer and Graves' disease. The present study was designed to report the prevalence of anatomical variations and developmental anomalies of the thyroid gland that will hopefully help to minimise the aforementioned complications related to thyroid surgery. A total of 52 male and 18 female properly embalmed cadavers were dissected. The thyroid gland was examined for the presence of the pyramidal lobe, levator glandulae thyroideae and partial or complete absence of isthmus. Length, greatest transverse and anteroposterior extent of both the right and left lobe of the gland was recorded. A pyramidal lobe was present in 43.9% male and 22.2% female cadavers and was more prevalent on the left side of the median plane. Levator glandulae thyroideae was present in 34.6% male and 27.8% female cadavers. Isthmus was absent in 9.6% male and 5.6% female cadavers. The average length, greatest transverse and anteroposterior extent of right lobe was 4.43, 2.54 and 1.69 cm, respectively, whereas for the left lobe it was 4.21, 2.63 and 1.7 cm, respectively. The nature of the specimens studied, and the region where the study is carried out, affect the different goitre zones, age, sex, and race of population studied, all of which can contribute to the anatomical variations of the thyroid gland found in different reports by various authors.