Absence of the isthmus of the thyroid gland: anatomical and clinical considerations

The right and left lobes of the thyroid gland are connected by an isthmus. The isthmus lies at the level of the second and third tracheal rings. Occasionaly, the isthmus may be absent. We hereby, report the absence of isthmus in a 52-year-old male cadaver of unknown origin. Both the right and left lobes were normal but they were separated. Both the right and left lobes of the thyroid gland measured 4.3 cm vertically. The separation distance between right and left glands was noted at the upper, middle and lower parts. The upper end of medial border of both lobes were separated by a distance of 1 cm while the separation distance was 0.7 cm and 1.5 cm at the middle and lower parts, respectively. The anatomical and clinical significance of absence of isthmus is important for medical personnel and the surgeons operating on the thyroid gland. The present case report is a an attempt to highlight such.