The Musculus constrictor pharyngis medius belongs to the pharyngeal musculature and belongs within this group to the Schlundschnürern. The upper pharyngeal gland (constrictor pharyngis superior) and the lower pharyngeal gland (constrictor pharyngis inferior muscle) directly adjoin the constrictor pharyngis medius muscle on both sides, but represent anatomical units that can be distinguished from it.
The three muscles develop at the embryonic stage from various gill arches, the constrictor pharyngis medius muscle arises from the fourth gill arch. It also contains the equipment for the internal and external laryngeal muscles (laryngeal musculature), for muscles of the esophagus as well as for various vessels, nerves and cartilage. The other two pharyngeal glands develop from the third and sixth gill arch.
The musculus constrictor pharyngis medius belongs to the skeletal musculature and can be influenced at will. In addition, it has a striated structure, whose pattern is formed by alternately arranged filaments within the muscle fibers.
Anatomically, the middle pharynx can be subdivided into two areas: the ceratopharyngeal pars and the chondropharyngeal pars.
Both parts of the constrictor pharyngis medius muscle originate from the hyoid bone (hyoid bone), but originate there in different places: the ceratopharyngeal parse begins at the small horn (cornu majus), whereas the pars chondropharyngea arises from the large horn (cornu minus). Between the two horns extends the hyoid bone (Corpus ossis hyoidei). The hyoid bone does not have its own connection to other bones, but hangs on the suprahyoid and infrahyoid muscles as well as some throat and tongue muscles.
At the throat (raphe pharyngis) is the approach of the constrictor pharyngis medius muscle. This is where the upper and lower pharyngeal thighs begin. Overall, the constrictor pharyngis medius muscle has the form of a fan or funnel. Nerve fibers connect the muscle with the pharyngeal plexus, which consists of branches of the ninth cranial nerve (glossopharyngeal nerve) and parts of the tenth cranial nerve (vagus nerve).
The constrictor pharyngis medius muscle participates in the process of swallowing and contributes to the formation of certain sounds, including deep vowels and pharyngeal sounds.
The swallowing act can be subdivided into a preparatory phase, which includes, for example, chewing and three transport phases. During the oral transport phase, especially the tongue muscles are active and push the food or liquid from the anterior mouth into the throat. This is followed by the pharyngeal transport phase, which is crucial for the constrictor pharyngis medius muscle.
First, the tensor veli palatini and the levator veli palatini muscle stretch the soft palate. The Constrictor pharyngis superior muscle produces a bulge in the nasopharynx (epipharynx) by contraction, also known as Passavant's ring bulge. This closes together with the soft palate access to the nose. The digastric muscle, the mylohyoid muscle and the stylohyoid muscle pull up the hyoid, together with the infrahyoid and suprahyoid musculature. At the same time, the thyrohyoideus muscle also causes the larynx to lift so that the epiglottis can close it.
At the same time, the upper esophageal sphincter dilates the esophagus. The circular sphincter is located in the upper esophageal junction (Constrictio pharyngooesophagealis) and forms the mouth of the esophagus. When all air passages are closed, the constrictor pharyngis medius contract, pushing the food or fluid further down the throat. The Musculus constrictor pharyngis inferior supports him. In the subsequent esophageal transport phase, the muscles of the esophagus finally take over the transport into the stomach. The whole process is highly automated and controlled by the brain's swallow center.
Damage to the constrictor pharyngis medius muscle is rarely isolated, but often affects other pharyngeal muscles as well as other structures. Functional failures of the muscle are often neuronal. Dysphagia, also known as dysphagia, can affect all phases and aspects of the swallow: from the occlusion of the nose and larynx to the lifting of the hyoid bone and the advancement of food. Sensitivity and salivation may also be affected.
As a cause of dysphagia numerous possibilities are considered. In addition to direct injuries (such as an accident), nerve damage is the most common reason. Radiation therapy for the treatment of breast cancer can accidentally injure the pharyngeal plexus, which also controls the constrictor pharyngis medius muscle. The vagus nerve and the glossopharyngeal nerve, together with the accessory nerve, traverse the jugular vein (foramen jugulare), through which blood vessels also pass.
Tumors, bleeding, swelling, injury, and other damage at this site often affect all three nerves, causing very complex clinical pictures. Neuromuscular and neurodegenerative disorders may also affect the fibers that control the constrictor pharyngis medius muscle. This also applies to brain injuries and circulatory disorders such as strokes and congenital neuroanatomical abnormalities.
Since the muscle constrictor pharyngis medius is not only involved in the swallowing process, but also contributes to the formation of certain sounds, motor speech disorders are also possible. Under certain circumstances, sufferers can improve their speech by logopedic training again. However, the success depends on the individual case.Tags: