An unusual variation of the omohyoid muscle and review of literature

The omohyoid muscle is important in radical neck dissection, as it is a landmark for this operation. Because it divides the anterior and posterior cervical triangles into smaller triangles and its particular relationship to the large cervical vessels, the presence of an anatomical variation of the omohyoid muscle is important. An unfamiliar muscle was found in the left anterior cervical region of a 57-year-old male cadaver. It was attached at its caudal end to the clavicle and coursed upward to the hyoid bone and a normal omohyoid muscle with its intermediate tendon was lateral to this muscle. Both the muscles joined together near the hyoid bone and both muscles attached to the hyoid bone with the same tendon. According to its origin and insertion, the unfamiliar muscle was considered to be the cleido-hyoideus muscle. In our case report, a variant of infrahyoid muscles is presented. Such an association constitutes an exceedingly rare condition.