Article
Macroscopical analysis of the thyroglossal duct with particular consideration of its topographical relationship to the hyoid bone
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Published: | July 6, 2010 |
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Introduction: The course of the thyroglossal duct (TD) is being discussed controversially in the literature. The aim of this study was to investigate the macroscopic identifiable characteristics of the TD and particularly its relationship to the hyoid bone.
Methods: A total of 77 half-heads from human cadavers cut in the mid-sagittal plane were examined. Nineteen of these specimens (age between 42–86 years) exhibited a pyramidal lobe of the thyroid gland and for this reason were dissected under a binocular loupe. Beginning from the pyramidal lobe the TD was identified and traced cranially to the hyoid bone and then to the base of the tongue.
Results: On one specimen the dissection succeeded just until the caudal edge of the hyoid bone, where the TD had a contact with the periosteum and was no more to trace. On the other 18 specimens the TD was extending cranially through the pre-epiglottic fat body dorsal to the hyoid bone. In five cases the exposure of the TD succeeded up to the hyoepiglottic ligament. Cystic changes of the TD were recognized. On three specimens the cysts were found cranial to the hyoid bone in the base of the tongue, on two specimens caudal to the hyoid bone and in one case dorsal to it.
Conclusions: The remnants of the TD could be identified on all the adult specimens with a present pyramidal lobe of the thyroid gland. The macroscopic examination revealed a course dorsal to the hyoid bone. Cystic remnants of the TD were found in all the possible places along the TD course including the base of the tongue.