Suprahyoid muscles are composed of three different originated muscles, including the first branchial muscles (the mylohyoid and the anterior belly of the digastrics muscle), the second branchial muscles (the stylohyoid muscle and the posterior belly of the digastrics muscle), and the occipital somite (the geniohyoid muscle). The history of the suprahyoid muscles indicate that those muscles might differentiate along the history of the jaw of the vertebrates. And the hyoid bone in the human being does not connect any other bonny or cartilaginous structures, while the hyoid bone or cartilage in the another vertebrate connecting with the other branchial structures or the skull. It could be considered that the hyoid bone in the human being could act as a fulcrum of the submandibular bone and a tractor of the larynx, and the suprahyoid muscles could play successively both rolls of the hyoid bone for according to the functions including mastication, swallowing, speech production, singing, expression, and so on.
