The mechanism behind this function is that when the nerve is stimulated, it causes forward movement of the tongue base which may result in the advancement of the palate by anteriorly displacing the anterior palatal pillar. Role in obstructive sleep apnoea: Studies have shown that if the nerve to the palatoglossus muscle is electrically stimulated, retropalatal space can be dilated which in turn aids in reducing the burden of obstructive sleep apnoea. The palatoglossus muscle along with the palatopharyngeus muscle functions to elevate the velar region and this in conjunction with the function of the levator veli palatini muscle provides velar positioning. Type IIIb glossectomy, also known as compartmental hemiglossectomy, includes the mucosa, submucosa, intrinsic muscles (transversalis, verticalis, inferior longitudinalis, and superior longitudinalis) and extrinsic muscles (genioglossus, hyoglossus, styloglossus and the inferior portion of the palatoglossus muscle) on the ipsilateral side of the lesion. The procedure of glossectomy can be divided into various categories based on the area of resection. Role in Glossectomy: During a surgical procedure for resecting tongue tumor, the area of resection is governed by the extent of tumor spread. For this, the palatoglossus muscle is cut and then the posterior palatal mucosa is sewed to the anteriorly resected margin. ĭuring the surgical procedure of zeta-pharyngoplasty, anterior mucosa gets removed, and splitting of the soft palate is done in the midline. By myotomy of the superior constrictor muscles and suturing of the lateral pedicle flaps to the palatoglossus muscle, the lateral pharyngeal wall is reconstructed. The lateral pharyngoplasty is a technique developed to act on these pathophysiological aspects of apnea. This collapse may exist because, during the expiratory-inspiratory transition, there may be a delay in the relaxation of the constrictor muscles. In patients with obstructive sleep apnoea, the lateral pharyngeal wall has been shown to collapse during the airflow as compared to patients without apnea. The primary mechanism in these individuals to approximate the tongue and soft palate during swallowing is tongue elevation rather than lowering of the soft palate. This action is based on a class III lever system where the force applied lies between the load and the fulcrum. However, this attachment is not favorable to lower the soft palate. In such instances, a considerable increase in the ability of the muscle to elevate the tongue exists. In some individuals, the attachment area of the muscle is relatively large into the anterior portion of the velum. This action is based on a class II lever system where the load (the bulk of soft palate) is present between the fulcrum (the posterior rim of the hard palate) and the force applied (action of the palatoglossus muscle). However, this attachment is favorable to lower the soft palate. In such cases, the mechanical ability of the palatoglossus muscle in elevating the tongue may be limited due to the lack of a rigid anchoring point towards which the tongue elevates. In some individuals, this region is near the uvula. Variation in the region of attachment of the palatoglossus muscle in the soft palate has been observed. The combined activity of both muscles provides a sling effect. This requires the palatoglossus muscle to pull in a downward and forward direction along with the activity of the palatopharyngeus muscle in a downward and backward direction. The pronunciation of uvular fricatives requires constriction of a smaller area (incomplete closure) of the isthmus. This is significantly affected by the activity of the palatoglossus muscle. According to some authors, during the pronunciation of vowels such as “u,” constriction of a larger area of the oropharyngeal isthmus is necessary. It has also been shown to be active in some individuals during speech. Also, it prevents the spillage of saliva from the vestibular region into the oropharyngeal region by maintaining the palatoglossal arch. This action plays a significant role during swallowing by propelling the food bolus towards the esophagus and occluding the oral cavity, thereby preventing retrograde flow of the food. It also draws the soft palate inferiorly, thereby narrowing the diameter of the oropharyngeal isthmus. The palatoglossus muscle functions to elevate the posterior portion of the tongue.
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