The unilateral cleidohyoideus accessorius muscle in human: A case report

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Chakorn Vorakulpipat
Tawepong Arayapisit
Panjit Chunhabundit
Varunya Chantadul


Objectives: The infrahyoid muscles are of clinical importance as they serve as anatomical landmarks especially for cervical metastases and surgery. Any variations in this region may cause misdiagnosis and complicate surgical procedures. This study aimed to present a muscular variation of the infrahyoid group, the cleidohyoideus accessorius or accessory cleidohyoid, to raise a concern about additional muscles in the neck region.

Materials and Methods: The infrahyoid region of 394 cadavers was dissected and investigated. The characteristics of the cleidohyoideus accessorius were then recorded.

Results: The unilateral cleidohyoideus accessorius was found in one of 394 Thai cadavers. The additional muscle co-originated with the right clavicular head of the sternocleidomastoid muscle and inserted at the body of the hyoid bone while other infrahyoid muscles were intact. The evolution and clinical considerations of the aberrant muscle were also included.

Conclusion: In the Thai population, the unilateral accessory cleidohyoid can be considered as a rare muscular variation; however, its clinical implications cannot be neglected. Thus, our study can support surgeons in preoperative planning and prevent any unfavourable outcomes.


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Vorakulpipat C, Arayapisit T, Chunhabundit P, Chantadul V. The unilateral cleidohyoideus accessorius muscle in human: A case report. M Dent J [Internet]. 2022 Mar. 23 [cited 2023 Dec. 7];42(1):63-8. Available from:
Case report


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