Which of the following describes the suprahyoid muscles?، The suprahyoid muscles make up a group formed by four muscles located in the anterior region of the neck above the hyoid bone , which inserted into it attach it to the skull. They are part of a subdivision of the anterior muscle group of the neck, topographically divided by the presence of the hyoid bone to facilitate its study.
which of the following describes the suprahyoid muscles?
Together, this group of muscles participates in the processes of chewing, swallowing and phonetic. In addition, together with the infrahyoid muscles contribute to the fixation of the hyoid bone, which is not articulated with any other bone.
They are located in three planes: a deep plane formed by the geniohyoid muscle, a medium plane constituted by the mylohyoid muscle and a superficial plane formed by the digastric and stylohyoid muscles.
Some literatures include the hyoglossus muscle as part of the suprahyoid muscles; however, in most of the bibliographies it is treated as an extrinsic muscle of the tongue, since it is not inserted superiorly in any bone structure unlike the rest of the suprahyoid muscles.
Geniohyoid muscle (deep muscle plane)
This muscle, being the deepest of the anterior muscle group and upper subgroup of the muscles of the neck, should be observed from the oral cavity, where it will be located below the genioglossus muscle.
The geniohyoid muscle is a small, short muscle that has a cylindrical shape. It is located above the digastric muscle and the mylohyoid muscle.
It originates in the lower mental spine of the mandible, also known as the inferior geni process, from where it begins a downward and backward course, culminating in inserting itself in the middle part of the anterior surface of the hyoid bone.
It is related to the contralateral geniohyoid medially, below it is related to the upper face of the mylohyoid (also known as the muscle of the mouth) and above it is related to the genioglossus muscle, which separates it from the tongue.
Mylohyoid muscle (middle muscular plane)
It is a square shaped muscle that forms the muscular floor of the mouth. It originates in the internal oblique line of the jaw, from where it goes down to insert itself in the hyoid bone and, medially, in the middle suprahyoid raphe; there he meets his contralateral counterpart.
It is related superficially and superficially with both bellies of the digastric muscles and, being the muscular floor of the mouth, its upper face is directly related to the oral cavity and the geniohyoid muscles.
The mylohyoid muscle participates in the conformation of the Pirogoff triangle, formed by the posterior border of the mylohyoid muscle, the middle tendon of the digastric muscle and the hypoglossal nerve. Said triangle contains the lingual artery.
Digastric muscle (superficial muscular plane)
It receives this name because it has the characteristic of being one of the few muscles of the human body that has two muscular bellies, one anterior and one posterior, joined by an intermediate tendon.
The posterior belly originates in the mastoid process, from where it goes forward and down to continue with an intermediate tendon that passes through the stylohyoid muscle.
Said intermediate tendon is fixed to the hyoid bone by a refractive pulley of fibrous tissue, formed by some musculotendinous fibers coming from the posterior belly of the muscle. At the same time, the intermediate tendon is joined to its counterpart by a set of intertwined fibers called interdigastric lamina.
Continue with the anterior belly that goes up, forward and towards the center, to insert into the digastric fossa of the jaw.
It is related by its posterior belly to the sternocleidomastoid muscle and the splenius of the head, which are also inserted into the mastoid process. Likewise, it is related to the internal jugular vein and the internal carotid and, a little later, to the parotid gland.
The posterior belly of the digastric muscle participates in the conformation of the Beclard triangle, conformed by the posterior border of the hyoglossus muscle, the greater horn of the hyoid bone and the posterior border of the posterior belly of the digastric muscle. This triangle contains the hypoglossal nerve and the lingual artery.
The anterior belly is related to its contralateral counterpart, with the submandibular gland and the superficial face of the mylohyoid muscle.
Stylohyoid muscle (superficial muscular plane)
It is a thin and elongated muscle that originates in the styloid process of the temporal bone and goes down and forward, ending in a tendon that bifurcates to allow the passage of the middle tendon of the digastric muscle.
It is inserted in the upper border, anterior face, of the body of the hyoid bone and is related to the posterior belly of the digastric muscle in its path. Medially it is related to the styloglossus muscle and the external carotid artery.
The suprahyoid muscles together fulfill the functions of chewing, swallowing and phonetics.
Because of its insertion in the hyoid bone and in different cranial bone structures, its primordial movements and those that are based on the performance of its functions are the descent of the jaw and the elevation of the hyoid bone.
Some lateral fibers of the mylohyoid muscle also contribute in the realization of lateral movements of the jaw in the process of mastication.
The descent of the jaw, which corresponds to the opening of the oral cavity, allows the entry of food into the cavity to initiate the digestive process; likewise, thanks to the movements of descent and laterality, the chewing process is allowed, to allow the destruction of the bolus for the consequent swallowing.
In the process of swallowing, the hyoid rises to assist in the descent of the food bolus, pushing it as it returns to its initial position.
The anterior muscles of the neck use the hyoid bone as an anchoring point to contract, and thus facilitate the descent of the alimentary bolus through the throat and into the esophagus.