FETAL ANATOMICAL VARIABILITY OF STRUCTURES IN INFRAHYOID AREA

Abstract

When performing myoplastic operations and surgical interventions on the thyroid gland, trachea and esophagus, information on the variant anatomy of the infrahyoid muscles, the features of their innervation and blood supply are of great clinical importance. Moreover, when additional muscles are attached to the thyroid gland, intraoperative bleeding can occur resulting in hematoma and tissue scarring in the postoperative period. There are fragmentary data in the literature on the variants of the structure and topography of the human infrahyoid area muscles. The specificity of branching nerves and blood vessels, their vascular-nervous relationships in a separate part of the sternohyoid, sternothyroid, thyrohyoid, and omohyoid muscles should be taken into account when performing rational incisions in the neck, moving both the flaps and the above muscles in plastic surgery. The purpose of study was to establish the anatomical variability and features of innervation and blood supply of the infrahyoid muscles of the neck in human foetuses of 4 – 10 gestational months age. Material and methods. The study was performed on 36 human foetuses, whose parieto-coccygeal length was 81.0 – 375.0 mm, without visible signs of anatomical abnormalities or anomalies in the cervical region. Thin sections of the structures from the anterior and lateral parts of the neck were prepared under the control of binocular magnifier, vascular injection technique, and morphometry. Foetal preparations weighing over 500.0 g were studied directly at Chernivtsi Regional Paediatric Pathological Bureau. Foetal preparations were taken from the Museum of M.G. Turkevich Human Anatomy Department, Bukovinian State Medical University. Results and discussion. The study demonstrated anatomical variability of the infrahyoid area muscles during the foetal period of human ontogenesis. Human foetuses were mainly found to have loose extending intramuscular branching of the nerves of the cervical loop in the infrahyoid muscles. The only exception is the inferior belly of the omohyoid muscle, where main nerve branching is found out. The distribution of nerves in the thickness of the infrahyoid muscles is uneven. Macroscopic examination revealed the smallest number of nerve branches was found within the middle third of the sternohyoid and upper third of the sternothyroid muscles. Arteries and nerves enter the sternothyroid and thyrohyoid muscles through the anterior surface, and the omohyoid and sternohyoid muscles enter mainly through the posterior surface of these muscles. The infrahyoid muscles are characterized by the main form of intramuscular branching of the arteries. The data on the peculiarities of intramuscular branching of arteries and nerves in the infrahyoid muscles we obtained, as well as the variant anatomy of the infrahyoid area muscles must be taken into account when performing a surgical access to the neck, or when operating on in the anterior cervical region, in particular myoplastic and reconstructive operations, in order to avoid muscle injuries.