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oai:docta.ucm.es:20.500.14352/1089222025-03-18T12:49:23Zcom_20.500.14352_14col_20.500.14352_15

00925njm 22002777a 4500 dc Kitamura, Kei author Suzuki, Ryu author Ishizuka, Satoshi author Murakami, Gen author Rodríguez Vázquez, José Francisco author Yamamoto, Hitoshi author Abe, Shinichi author 2024-06 Background: In adults, the intermediate tendon of digastricus muscle usually runs along the medial or lateral side of the stylohyoideus muscle insertion. To provide a better understanding of the variations, we examined the topographical anatomy of the muscle and tendon in fetuses. Methods: We examined histological sections from six early-term, 26 mid-term and six near-term fetuses (approximately 8–9, 12–18 weeks and 25–33 weeks). Results: At early-term, an initial sheath of intermediate tendon of digastricus muscle received the stylohyoideus muscle at the superior aspect. The muscle and tendon was distant from the hyoid. At mid-term, near the insertion to the hyoid greater horn, the stylohyoideus muscle consistently surrounded more than 2/3 of the intermediate tendon circumference. In contrast, we found no near-term specimen in which the stylohyoideus muscle surrounded the intermediate tendon. The multilayered tendon sheath was fully developed until near-term and connected to the body of hyoid by an intermuscular septum between the thyrohyoideus muscle and one or two of suprahyoid muscles. Therefore, the hyoid insertion of the styloglossus muscle was a transient morphology at mid-term. Conclusion: The stylohyoideus muscle insertion was appeared to move from the tendon sheath to the hyoid greater horn and, until near-term, return to the tendon sheath. A fascia connecting the tendon sheath to the body of hyoid was strengthened by the suprahyoid and infrahyoid muscles. The latter muscles seemed to regulate fixation/relaxation of the intermediate tendon to the hyoid. The stylohyoideus muscle slips sandwiching the intermediate tendon might be a rare morphology. Kitamura, K., Suzuki, R., Ishizuka, S., Murakami, G., Rodríguez-Vázquez, J. F., Yamamoto, H., & Abe, S. I. (2024). Growing stylohyoideus muscle insertion to the hyoid bone with special reference to its topographical relation to the intermediate tendon of digastricus muscle: A histological study using human fetuses. Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft, 254, 152246. https://doi.org/10.1016/j.aanat.2024.152246 0940-9602 10.1016/j.aanat.2024.152246 https://hdl.handle.net/20.500.14352/108922 https://doi.org/10.1016/j.aanat.2024.152246 https://www.sciencedirect.com/science/article/pii/S0940960224000384?via%3Dihub Growing stylohyoideus muscle insertion to the hyoid bone with special reference to its topographical relation to the intermediate tendon of digastricus muscle: A histological study using human fetuses