Suprahyal Muscles: Structure, Function & Diseases

The suprahyal musculature is located at the floor of the mouth and has the function of pulling the hyoid bone upward. It is formed by four muscles and serves to open the jaw directly. By lifting the floor of the mouth, it is significantly involved in chewing, swallowing and speaking. It is also referred to as the upper hyoid muscles. Its counterpart is the infrahyal muscles, which pull the hyoid bone downward.

What is the suprahyal musculature?

The hyoid bone, a two- to three-inch curved bone below the tongue, is suspended only by its muscles and ligaments at the base of the skull and has no direct connection to the skeleton. It thus functions like a swing, with the larynx and trachea located at its lower end. This structure gives the tongue its great mobility. A fracture of the hyoid bone indicates the use of force against the neck, for example by strangulation, which is why it is examined superficially during an autopsy. The hyoid bone supports the base of the tongue and can be palpated from the outside between the neck and the floor of the mouth as well as easily moved.

Anatomy and structure

The superior hyoid muscles act on the hyoid from the side of the head, while the inferior ones act accordingly from the neck region. The suprahyoid (also suprahyoid) muscle group includes the digastric muscle, the mylohyoid muscle, the stylohyoid muscle, and the geniohyoid muscle. The digastric muscle is described as having two bellies, is located on the external floor of the mouth, and is connected laterally to the hyoid bone by means of a switch tendon. The anterior of its two bellies runs obliquely anteriorly to the inner side of the chin, and the posterior runs obliquely posteriorly to the base of the skull. Parallel to the posterior belly is the stylohyoid muscle. Right and left geniohyoideus (chin-tongue bone) muscles lie immediately adjacent to each other in the upper region of the floor of the mouth. Together, the suprahyoid muscles pull the larynx (larynx), which is suspended from the hyoid bone, toward the posterior end of the tongue. There, the epiglottis (covering of the throat) bends and overlays the laryngeal inlet. This guarantees that nothing enters the “wrong throat” during swallowing. Then, the infrahyal muscle groups return the larynx and hyoid bone to their respective starting positions.

Function and tasks

Together, the superior and inferior hyoid muscles form a sling that surrounds and can fix the hyoid bone. Only with this, for example, the process of opening the mouth becomes possible. Every tongue movement also works in this way. The entire hyoid musculature is also involved in bending the cervical spine and the head. Even as breathing musculature the muscle loop can function if necessary. The tension of the suprahyal muscles is also significant for the optimal functioning of the temporomandibular joint, the mobile connection between the lower jaw and large parts of the skull. If asymmetries occur in this area (for example after dental treatment) that are not corrected, this can have negative effects on the reliable interaction of the hyoid muscles. As a result, the masticatory muscles are often affected as well. In addition to the many different muscle cords, the human tongue is also traversed by four large nerve tracts. Through these, the tongue is connected to internal organs such as the liver and the stomach. If diseases or deficiencies appear there, changes in the tongue or also in the oral mucosa (shape, color) often indicate this immediately. In this respect, the tongue is considered a kind of showcase of the digestive tract. Certain coatings on the tongue can be associated by any physician with diseases of the internal organs. If the mobility of the tongue is restricted or if discomfort during swallowing is noticeable, injuries or inflammations of the suprahyal musculature can also be a cause.

Diseases

A healthy tongue is mobile in all directions, pale red in color, and always moist. The surface is usually smooth. A thin whitish coating on the surface of the tongue indicates that the digestion of food in the stomach is proceeding in the right way. However, a changed appearance of the tongue can also indicate mostly harmless diseases in the oral cavity itself. One example is “hairy tongue”, which manifests itself with a conspicuous keratinization of the tongue surface. In these cases, sufferers have the feeling that hair is growing on their tongue.Blackening of the tongue (“lingua nigra”) can come from excessive smoking and is not yet a dangerous disease at first. However, besides nicotine, heavy alcohol consumption and also the insidious papilloma viruses are basically enemies of a healthy tongue. In their aggressive forms, these can, under certain circumstances, promote serious cancerous tumors that nestle in the cervix, oral cavity or larynx. The tongue itself can also be affected by a cancer. A burning tongue when eating highly acidic foods may already be an indication of tongue cancer. It becomes alarming when small ulcers develop on the tongue that do not disappear within four to six weeks. An emerging tongue cancer is often accompanied by functional losses of the tongue, which are associated with damage to the suprahyal musculature. These impairments are particularly noticeable in speaking, swallowing and tasting. Preventive against many diseases of the tongue or mucous membranes is a thorough and regular tongue cleaning. If changes occur on the tongue surface, a doctor should be asked for advice in good time.