Spatio-Temporal Morphological Changes of Structures in Infrahyoid Triangles in Human Fetuses During Fetal Period of Human Ontogenesis

Abstract

Infrahyoid triangles in anterior region of neck contain crucial structures for human body like trachea, thyroid gland, nerve plexuses and magistral blood vessels. Infrahyoid muscle flaps are often used for reconstructive surgeries that is why the topography of their innervation is important for successful dissection and minimization of postsurgical complications. That is why the aim of our study was to examine topographical peculiarities of structures in infrahyoid triangles in human fetuses during late intrauterine prenatal development (PND) that would provide clinical practitioners like pediatric and oncologic surgeons with additional anatomic data. We have examined 18 specimens of human fetuses (4-9 th month of PND, 82,0-311,0 mm of parieto-coccigeal length (PCL)). All material was obtained and studied at Chernivtsy Regional Pathologists Office (Ukraine) in accordance with bilateral collaboration with the Department of Histology, Cytology and Embryology of BSMU. To reach the aim of the research we have used classic morphological methods (anthropometry, morphometry, layered dissection) as well as injection of the blood vessels (in 6 specimens by the means of dies) and three-dimensional reconstructioning. The study was performed in accordance with the provisions of the Declaration of Helsinki on ethical issues of studies conducted with humans (1964-2008). We have seen that in fetal period of human PND (80,0-310,0 mm of PCL) ansa cervicalis, that provides innervation for infrahyoid structures, is formed by anastomosis of the superior and inferior roots (C2 and C3) that are merging with internal carotid artery and internal jugular vein. The infrahyoid muscles receive nourishment predominantly from the superior thyroid artery, that is a branch of external carotid artery (91 %) or rarely bifurcation (3 %) and either as a branch of common carotid artery (6 %). Specific feature of infrahyoid triangles during fetal period of PND is the fact that it highly relies on bony boundaries such as mandible, sternum and clavicle that haven't reached their mature morphology at 3 rd month of PND. Investigations of topographical peculiarities of structures in infrahyoid triangles in fetal period of PND are important for successful reconstruction surgeries in postnatal and adult age.