The mylohyoid muscle is the maxillary hyoid muscle that runs above the hyoid bone and originates from a fine bony ridge on the inside of the lower jaw. Tension in the maxillary hyoid muscle can be responsible for difficulty swallowing and other health disorders.
What is the mylohyoid muscle?
The hyoid bone (Os hyoideum) is surrounded by two muscle groups, divided into internal (intrinsic) and external (extrinsic) muscles. The mylohyoid muscle, like the digastric muscle and the stylohyoid muscle, belongs to the upper hyoid muscles and has the ability to pull up the hyoid bone. The lower hyoid muscles, sternohyoid, thyrohyoid and omohyoid muscles, are responsible for pulling it down. The maxillary hyoid muscle, along with the other muscles, leads toward the jaw and neck muscles, and there are also connections down to the shoulder blades and rib cage. Because the hyoid bone is very deep, the elongated mylohyoid muscle is one of the most interwoven muscles in the head region. The skeletal muscle attached to the hyoid bone is connected with its posterior fibers to the hyoid body, while the other hyoid muscles meet with their anterior fibers in the connective tissue adhesion line of the median plane (raphe mylohyoidea). The mylohyoid muscle also provides functional tissue supply. The entire hyoid musculature supports tongue movement, speech, breathing, swallowing, coughing, laryngeal movement, mouth opening, and masticatory system. The mandibular hyoid muscle specifically serves to elevate the hyoid bone and open the mandible.
Anatomy and structure
The mylohyoid muscle is a derivative of the first gill arch and is also called the diaphragma oris. The soft floor of the mouth between the mandible and hyoid bone is formed primarily by the left and right maxillary hyoid muscles. Both tongue muscles connect via the raphe mylohyoidea and come together to form a continuous muscular plate. Beneath the tongue at the base of the mouth is the hyoid bone, a curved U-shaped bone that is the only one not connected to the skeletal system. It is attached to the tongue muscles and ligaments that anchor it to the base of the skull. The tongue muscles allow the hyoid bone to support the weight of the tongue. Without this function, humans could not speak or articulate words. The mylohyoid muscle raises the hyoid bone during swallowing and opens the jaw, while the geniohyoid muscle acts as the chin hyoid muscle to move the hyoid bone forward. Responsible for hyoid elevation are also the digested digastrica muscle at the chin projection and the split stylohyoideus muscle at the small hyoid horn. The mandibular salivary gland is also located at the posterior border of the mylohyoid muscle under the floor of the mouth.
Function and tasks
Every day, humans consciously or unconsciously use their tongue muscles, for example, to moisten their lips. In addition to opening the jaw, the mylohyoid muscle is also involved in the swallowing process and grinding movements. Together with the other intrinsic and extrinsic muscles, the planar hyoid muscle guarantees the undisturbed functioning of the tongue during food intake and during an unrestricted chewing and speaking process. The intrinsic tongue muscles are capable of deforming the tongue and are activated by the seventh cranial nerve (hypoglossal nerve). The external tongue muscles are able to move the tongue throughout the oral cavity, raising lowering, advancing and retracting it. The mylohyoid muscle performs specific tasks that are subject to constant alternation of movement and tension. The larynx and trachea are connected to the hyoid bone. During the act of swallowing, certain muscles of the tongue pull upward together with the larynx and close the laryngeal inlet by pressing the laryngeal lid against the inside of the throat. The mandibular hyoid muscle forms a stable connection to the floor of the mouth. Moreover, the mylohyoid muscle influences the cervical muscles and is also involved in the coordination of movement of the neck and shoulder. There are no muscles directly over the hyoid bone, which is why it is palpable through the skin. Because the hyoid muscles extend from the jaw, chest and shoulder to the tongue, they are a significant component of various movement patterns.The muscles at the hyoid bone and the thyroid cartilage as the largest laryngeal cartilage are among the most important forms of movement in the neck, head and trunk.
Diseases
If poor posture or breathing difficulties occur, medical professionals rarely consider problems with the hyoid bone and surrounding tongue muscles. If the hyoid bone is only loosely fixed with weak hyoid muscles and lies too far back, a mandibular recession can occur. As a result of this jaw malposition, narrowing of the trachea occurs, which can trigger problems with breathing. In speech therapy, tongue function plays an important role in speech development. By training the tongue and mouth muscles, various speech and swallowing disorders can be treated. Tension of the mylohyoid muscle or the other tongue muscles can also lead to a variety of health restrictions. If the hyoid muscles are impaired in their mobility, the tension often results in swallowing difficulties, headaches or neck stiffness. If children suffer from an incorrect resting position of the tongue, mouth breathing is favored instead of correct nasal breathing. In this case, the tongue is not located on the palate in the resting position, but on the floor of the mouth, which results in slack tongue muscles and possibly the development of an excessively large lower jaw. If the tongue falls backward when sleeping in the supine position, airflow is obstructed, which can lead to snoring or even cessation of breathing. To combat potentially life-threatening sleep apnea, physicians now use tongue pacemakers that stimulate certain tongue muscles and the lingual nerve. Treatment of sleep apnea also involves targeted tongue muscle training that strengthens the suprahyoid muscle group, which includes the mylohyoid muscle. This method of therapy uses electrical stimulation over a period of four to eight weeks and can significantly improve parameters in nocturnal breathing disorders.
